ON PLAINTIFF’S MOTION AND DEFENDANT’S CROSS-MOTION FOR SUMMARY JUDGMENT
This matter is before the Court of Claims on cross-motions for summary judgment. There are no disputed issues of fact. For reasons hereafter given, plaintiff’s motion is granted, and defendant’s cross-motion is denied.
This is a suit based upon a fixed-price, indefinite-quantity contract (No. AF 04(606)-7880), between the defendant, acting through the Department of the Air Force, and plaintiff.1 Under said contract, plaintiff was to supply diesel generator sets, both skid and wheel mounted, known as the MB-Teen series (MB-15 through MB-19), which vary in capacity from 15 to 150 kilowatts. Defendant agreed to order certain minimum quantities specified in the contract schedule, and plaintiff agreed to furnish, when ordered by defendant, additional quantities of each item up to the maximum quantities specified in the schedule.2 *426The schedule also set forth the prices at which the items were to be furnished.
The basic dispute before the court is whether certain orders were “issued” within the time period specified in the contract.
Part XIII of the contract, the provision in question, provided:
CONTRACT PERIOD: Any resulting contract shall be effective and binding as of the date of approval thereof * * * and shall remain in effect * * * until all items ordered have been accepted by and delivered to the Government. The Government reserves the right to issue orders against this contract for a period not to exceed eighteen (18) months from date of approval of the Contract. [Emphasis supplied.]
The contract was subject to the written approval of the Secretary of the Air Force and expressly stated that it would not be binding until so approved. Plaintiff and defendant are in full agreement that the contract was duly approved on March 11, 1961, and thus, under the terms of the contract, became effective on that date.
The contract provided that Order No. 1 for the minimum quantities would be issued at the time of the award of the contract. Order No. 1 was mailed to plaintiff with the contract on March 11, 1961, the date the contract became effective. Nine more orders were placed from time to time. These orders were termed “calls.”
Call No. 1 ordered quantities substantially in excess of the minimum contract quantities. Plaintiff admits that Call Nos. 2 through 7 were issued within the contractual time limitation. However, plaintiff contends that the calls in the following table were issued after termination of defendant’s contract right to place additional orders:
Date of Order
Description
Amount
Date mailed
Date received
9/10/62 Call 10 ...................$ 11,119.64 9/10/62 After 9/11/62
9/11/62 Call 8 .................... 1,120,891.17 9/11/62
9/11/62 Call 9 .................... 89,544.18 9/11/62
9/11/62 Modification 1 to Call 8 .... (314,699.00) 9/17/62 After 9/17/82
9/11/62 Modification 1 to Call 10____ 314,699.00 9/17/62
Since defendant insisted plaintiff supply such orders, plaintiff contends it is entitled to recover the difference between the reasonable value of the additional sets and the amount paid by defendant.
On September 17, 1962, defendant mailed Modification 1 to Call No. 8, dated September 11, 1962, which was received by plaintiff after September 17, 1962. The items deleted by Modification 1 to Call No. 8 were identical to the items added by Modification 1 to Call No. 10. Defendant states that the only effect of this transfer was that the items would be delivered, invoiced, and paid for under Call No. 10 instead of under Call No. 8.
Plaintiff gives two reasons for its contention that Call Nos. 8 through 10 were not timely ordered by defendant within the period specified in the contract: (1) The 18-month period during which orders under the contract could be issued commenced on March 11, 1961, the effective date of the contract, and thus expired on September 10, 1962; (2) an order was not “issued” under the contract until it was received by the contractor, and thus, since Order Nos. 8 through 10 were received after September 11, 1962, they were untimely even if the 18-month period is computed in the manner suggested by defendant. If the plaintiff is correct *427on either contention, it is entitled to recover.
In reference to the above contentions, defendant argues that the orders were timely because (1) the first day of the contract should be excluded so that the 18-month period commenced on March 12, 1961, and expired on September 11, 1962; (2) the mailing of such orders by defendant on September 10, 1962 (Call No. 10), and September 11, 1962 (Call Nos. 8 and 9), was issuance under the contract, and the date of receipt is irrelevant.3
However, plaintiff’s position, as described above, was not always so well defined. Round 1 of the dispute was signaled by plaintiff’s letter of September 25, 1962, in which plaintiff’s contract administrator advised defendant’s contracting officer that the issuance of Call Nos. 8 and 9 had been exercised beyond the 18-month contract period. No mention was made of Call No. 10. Plaintiff expressed its willingness “to negotiate this additional quantity if you [defendant] so desire.” On September 28th, the Government replied by letter that Call Nos. 8 and 9 “were issued 11 September 1962, which is within the time period set forth” in the contract.
This led to another letter by plaintiff’s contract administrator, dated October 1st. After citing the provision of the contract which gave the Government the right to issue orders for a period of 18 months from the date of approval of the contract, the letter (1) made the erroneous observation that the date of approval of the contract was March 10, 1961, and (2) concluded from this that the contract period terminated on September 10, 1962, and therefore Call Nos. 8 and 9 were not exercised within the contract period. Plaintiff did not dispute the assertion in defendant’s September 28th letter that Call Nos. 8 and 9 were “issued” on September 11, 1962. On October 4, 1962, plaintiff’s contract administrator sent a letter returning Call Nos. 8 and 9, “which have been issued after the expiration of the contract period * '* Both returned calls had been mailed by defendant on September 11, 1962. However, plaintiff did not return Call No. 10, which had been mailed September 10th and received by it after September 11, 1962.
The Government responded by a letter dated October 9, 1962, in which it pointed out that the contract actually became effective March 11, 1961, contrary to plaintiff’s erroneous assumption that it had become effective March 10th. “Therefore,” the letter continued, “since Calls #8 and #9 were issued 11 September 1962, they were issued within the time period defined in subject contract for this issuance.”
On October 23, 1962, plaintiff’s contract administrator responded in a letter in which he explained the source of his erroneous assumption that the contract became effective March 10th. He acknowledged that plaintiff’s “calculations of the time period allowable for the issuance of Call orders were based upon the date of 10 March 1961.”
Judging from plaintiff’s mistaken assumption that the contract was effective March 10th and from the correspondence presented thus far, it is reasonable to assume that plaintiff had not yet taken the position that issuance was accomplished by receipt or that the effective date of the contract was to be included in computing the 18-month period. Rather, plaintiff’s initial position seems to have been that, since the effective date of the contract was March 10, 1961, then all calls were untimely if mailed after midnight September 10, 1962 (a computation presumably arrived at by excluding the erroneous March 10th effective date and computing from March 11, 1961, to September 10, 1962).
However, once plaintiff became aware that March 11th was the effective date, it changed its method of computing the *42818-month period, and by letter dated January 21, 1963, plaintiff’s vice president advised the Government that it remained firm in its position “that Calls #8 and #9 and Modification #1 to Call #10 were not exercised within the time period specified in the subject contract.” The letter further stated, that, even on the basis of a March 11th effective date, “the contract period of 18 months from date of approval (11 March 1961) is midnight the 10th of September 1962. All calls exercised beyond 12:00 midnight the 10th of September 1962 are therefore not within the contract period.” On January 28, 1963, defendant’s contracting officer, by telegram, reaffirmed his position that Call Nos. 8 and 9 were issued within the contract time period and directed plaintiff to produce the generator sets involved. This direction was confirmed by the contracting officer’s letter to plaintiff, dated February 5, 1963. The contracting officer also noted in that letter that “Because of the Government’s urgent need for these generator sets, we would appreciate a current production report on these two calls.” Plaintiff, in its reply of February 8,1963, reasserted the position stated in its January 21st letter and further stated that, since the Government had directed it to honor the disputed calls, it would do so, but would process a claim under the “disputes” clause of the contract.
On March 8, 1963, the contracting officer issued a formal decision disallowing plaintiff’s claim, holding that the 18-month period for issuing calls did not expire until midnight September 11, 1962, and therefore Call Nos. 8 and 9 were properly executed.
On April 10, 1963, plaintiff filed a pro se appeal with the Armed Services Board of Contract Appeals (hereinafter “Board”), contending that Call Nos. 8 and 9 and Modification 1 to Call No. 10 were issued beyond the authorized time limit. The following sentences in plaintiff's appeal indicate that, at that point, plaintiff had not yet taken the position that receipt constituted “issuance” under the contract:
SUMMARY
******
6) Call No. 8 was issued on 11 September 1962, one day after the termination of the 18 months allowed by Part XIII. * * *
7) Call No. 9 was issued on 11 September 1962 (Exhibit 6)
8) Call No. 10 was issued on 10 September 1962 (Exhibit 7)
Plaintiff then retained counsel who decided to raise the issue that timeliness of the calls must be determined on the basis of their date of receipt. Although the parties agreed that a formal amendment of the appeal letter would not be necessary, plaintiff did take the position before the Board that Call Nos. 8, 9, and 10 were untimely because they had been received by plaintiff after September 11, 1962.
The reason the above correspondence has been so laboriously outlined is that the Board relied heavily upon it in its June 10, 1963, decision denying plaintiff’s appeal. In concluding that Call Nos. 8, 9, and 10 were issued within the contract period, the Board held that the 18-month period was to be determined by excluding the day the contract was approved, following the general rule of excluding the day from which the time is to begin to run and including the last day of the time period specified.
With respect to the question of ’ the effective date of the exercise of the calls, the Board held that the disputed calls were effective on the date of mailing, not on the date of receipt. The Board said the wording of the contract itself did not demand either conclusion, but it based its holding on the correspondence outlined above and, in particular, upon plaintiff’s failure to challenge Call No. 10. The Board concluded that this correspondence showed it was the intent of both parties that, within the meaning of the contract, the date of mailing should be the date of “issue.”
*429Plaintiff filed its petition in this court on October 28,1964, alleging in substance that Call Nos. 8, 9, and 10 were not timely under the contract and that, therefore, as to such items, plaintiff should recover its costs and a reasonable profit thereon, which plaintiff states amounts to an additional $781,946.14, plus $70,000 deducted by the defendant as a price discount of $1,000 each for 70 production units. Plaintiff’s theory is that the untimely calls made by defendant constituted a breach of the contract or a contract implied in fact.
Both parties moved for summary judgment, and the matter was referred, pursuant to Rule 54(b), to one of the court’s trial commissioners. The trial commissioner recommended that plaintiff’s motion be denied and defendant’s motion be granted, holding that (1) the 18-month period commenced March 12, 1961 (the day after the approval of the contract), and terminated September 11, 1962, and (2) the calls were effective on the date of mailing. He based his conclusion primarily on what he interpreted as the intent of the parties, as evidenced by the correspondence described above. We find both the Board and our commissioner in error. For reasons to be explained herein, we find that receipt — not mailing— constitutes issuance, and therefore Call Nos. 8, 9, and 10 were not issued within the 18-month limitation specified in the contract.
To begin with, we must answer defendant’s contention that the Board’s decision turns on factual issues and, therefore, is entitled to finality. The defendant reasons as follows: (1) Since the contract provisions in question did not contain any specific language to indicate when an order is deemed to have been issued, it became necessary to consider the acts of the parties under the contract in order to ascertain the meaning intended; (2) after considering such acts, the Board found the parties intended that the Government should have the right to issue orders under the contract by mailing such orders at any time up to and including September 11, 1962; (3) the question of the intent of the parties is a question of fact.
This argument is nothing but semantic sophistry and does not warrant much discussion. Under the express language of both this contract and the Wunderlich Act, 41 U.S.C. §§ 321-322, the Board is entitled to finality only as to questions of fact. That act specifically provides, 41 U.S.C. § 322, that “No Government contract shall contain a provision making final on a question of law the decision of any administrative official, representative, or board.” This statutory mandate is incorporated into this contract via the standard disputes clause which, by its terms, extends only to “any dispute concerning a question of fact arising under this contract,” and which further provides “That nothing in this contract shall be construed as making final the decision of any administrative official, representative, or board on a question of law.”
It has been consistently held by this court that the interpretation of the language of a contract is a question of law, not a question of fact, and thus prior administrative determination on such a question is not final or binding on the court. Hol-Gar Mfg. Corp. v. United States, 351 F.2d 972, 974, 169 Ct.Cl. 384, 386 (1965), and eases cited; Copco Steel & Eng’r Co. v. United States, 341 F.2d 590, 595, 169 Ct.Cl. 601, 610 (1965), and cases cited.
The questions before the Board were how the 18-month period specified in the contract was to be computed and whether mailing or receipt constituted “issuance” under the contract. The Board cannot convert these clearly legal issues of contract interpretation into factual issues simply by resolving them in terms of the intent of the parties. For it is always true that “in the case of contracts, the avowed purpose and primary function of the court is the ascertainment of the intention of the parties.” 4 Willis-ton, Contracts § 601 (3d ed. 1961), quoted with approval in North Am. Philips Co. v. United States, 358 F.2d 980, 982, 175 Ct.Cl. 71, 75 (1966), and Chase & Rice, *430Inc. v. United States, 354 F.2d 318, 321, 173 Ct.Cl. 740, 745-746 (1965).
The intent of the parties is the ultimate legal conclusion, not a factual matter. If the Board could make binding decisions on matters of contract interpretation merely by speaking in terms of the intent of the parties, the Wunderlich Act would be robbed of much of its purpose. Accordingly, this court is not bound by the Board’s decision, but is free to decide this case in accordance with its own view of the law.
The Government next contends that, even if the Board’s findings were not binding, both the Board and our trial commissioner were on sound ground in relying upon the conduct of the parties as an indication of their intent. Again we disagree.
The conduct relied upon was the correspondence of the parties (as outlined above) and the position taken by plaintiff in the initial appeal letter it filed with the Board. For the sake of argument, it can be assumed that this correspondence reveals that once it was obvious that a dispute had arisen, plaintiff originally took a position consistent with defendant’s contention that mailing constituted issuance of an order. Not until plaintiff filed its brief with the Board did it assert that calls were effectively exercised only when received by plaintiff. (See p. 428, supra.)
However, the significant point here is that the correspondence referred to was written after the dispute arose. It is well settled that the practical interpretation of a contract, as shown by the conduct of the parties, is of great weight in interpreting the contract. General Warehouse Two, Inc. v. United States, 389 F.2d 1016, 181 Ct.Cl.-(Oct. 1967) and cases cited; Universal Match Corp. v. United States, 161 Ct.Cl. 418, 422 (1963), and cases cited. However, this rule only applies to conduct “during performance,” 4 and “ ‘ * * * prior to the time when the contract becomes subject to controversy,’ * * *. [Emphasis supplied.] Union Paving Co. v. United States, 115 F.Supp. 179, 185, 126 Ct. Cl. 478, 489 (1953).” 5 Only the action of the parties “before a controversy arises is highly relevant in determining what the parties intended.” [Emphasis supplied.] Northbridge Electronics, Inc. v. United States, 175 Ct.Cl. 426, 438 n. 8 (1966).
In the instant case, plaintiff’s very first letter was written on September 25,1962, approximately 2 weeks after the contractual period for making calls under the contract had expired. It was readily apparent at this time that a dispute had arisen — defendant was contending that certain calls were timely issued under the contract, and plaintiff was contending that they were not. Therefore, as the circuit court said in the case of El Paso Natural Gas Co. v. Kelly, 308 F.2d 820, 822 (10th Cir. 1962), “[T]he rule that courts will generally apply an interpretation given by the parties to a doubtful contract * * * is not applicable here as the letters were written during negotiations to settle the dispute * * •» ”
Lacking relevant conduct prior to the time the dispute arose, the court must therefore be guided by the usual legal effect which the disputed contract provisions would bear in light of applicable judicial precedents and legal principles. For unless the conduct of the parties, or the contract read as a whole, manifests a contrary intent, we should assume the parties intended that normal legal authority and precedents would control.
In analyzing this contract, it cannot be seriously disputed that the portion in question is most accurately characterized as an option contract. As related above, Part VIII (“Orders”) of the Special Provisions provides:
* * * The Contractor agrees to furnish to the Government, when ordered, the supplies or services set forth *431in the Schedule up to and including the quantity designated in the Schedule as the “maximum quantity”. * * *
Williston describes an option as “ ‘the obligation by which one binds himself to sell and leaves it discretionary with the other party to buy * * 1 Williston, Contracts § 61A at 199 (3d ed. 1957), citing Black v. Maddox, 104 Ga. 157, 30 S.E. 723 (1898). In the instant case, plaintiff bound itself to sell the additional units should defendant, at its discretion, order them within the contract period.
Corbin, in a lengthier description, states that the primary element of the option contract “is that the option Holder has the legal power to consummate a second contract for the contemplated exchange of equivalents and at the same time the legal privilege of not exercising it. The option giver, on the other hand, has the correlative liability to become bound to execute that exchange, and at the same time a disability to avoid it.” 1A Corbin, Contracts § 259 at 464 (1963 ed.). This description also clearly encompasses the instant contract. Similarly, McBride & Wachtel, a recognized authority in the field of Government contracts, refers to this type of contract as an “indefinite quantities option contract” and as an “option contract.” 6
The following comment at page 7 of the decision of the Armed Services Board of Contract Appeals demonstrates that the Board also characterized the contract as an option contract:
-* * * [T]he Government had an option (but not an obligation) to issue orders during the 18-month period from date of approval of the contract. * * -x- [w]e conclude that the Government was obligated to order the minimum quantities on 11 March 1961 and that thereafter * * * it had a right, at its option, to issue additional orders.
The Government employs the identical language on page 42 of its brief, so it appears to agree with this characterization of the contract. The definition of options in the Armed Services Procurement Regulations sheds further light on the Government’s view in this area (ASPR 1-1502, 32 C.F.R. § 1.1502 (1967)):
1.1502 Definition.
As used in this subpart, an option clause is a provision in a contract under which, for a specified time, the Government may elect to purchase additional quantities of the supplies and services called for by the contract, or may elect to extend the period of performance of the contract.
This definition also obviously covers the disputed contract.
Turning now to the general rule governing exercise of an option, it is well settled that notice to exercise an option is effective only upon receipt. For example, Corbin, after distinguishing the rule governing acceptance of offers, comments as follows on the exercise of options :
* * [W]hen, by the terms of an already consummated contract it is provided that one party shall have power to produce certain legal results by giving notice, it is usually held that this means notice received in fact and not merely notice mailed. * * * In a contract to ship goods as ordered, there is no duty of immediate performance until an order is received. * *
If in an option contract the duty of the promisor is conditional on “notice within 30 days”, does this mean notice *432received or notice properly mailed ? It is believed that, in the absence of an expression of contrary intention, it should be held that the notice must be received. * * * The rule that an acceptance by post is operative on mailing was itself subjected to severe criticism; and, even though it may now be regarded as settled, it should not be extended to notice of acceptance in already binding option contracts. * * * [1A Corbin, Contracts § 264 at 521 (1963 ed.).]
The courts are in general agreement with this rule. “It is at least the majority rule that notice to exercise an option is effective only upon its receipt by the party to be notified unless the parties otherwise agreed.’’ Cities Serv. Oil Co. v. National Shawmut Bank, 342 Mass. 108, 172 N.E.2d 104, 105 n. 1 (1961). See also Scott-Burr Stores Corp. v. Wilcox, 194 F.2d 989 (5th Cir. 1952) (option to renew a lease held not timely exercised because received after 12-month notice period though mailed within such period), and cases collected at 1A Corbin, Contracts, § 264 at 521-22 n. 50 (1963 ed.).
Finally, a reading of the Armed Services Procurement Regulations, ASPR 1-1505, 32 C.F.R. § 1.1505 (1967), indicates that the Government itself recognizes the validity of the general rule. 1.1505 Exercise of options.
(a) The exercise of an option by the Government requires the contracting officer’s written notification to the contractor within the time period specified in the contract.
It is agreed that Call Nos. 8, 9, and 10 were all received by the contractor after midnight September 11, 1962. Applying the general rule to the instant case, we therefore hold that all three disputed calls were exercised after the expiration of the 18-month period, no matter which computation is accepted. For even by the Government’s computation (ex-eluding the first day (March 11, 1961) and including the last day), September 11, 1962, is the last day of the period. Accordingly, this disposition of the case makes it unnecessary to decide the issues pertaining to the computation of the contract period.
Defendant’s final contention is that, even if the contract period had expired when Call Nos. 8, 9, and 10 were issued, plaintiff is still not entitled to recover. Defendant’s theory is essentially as follows: Since plaintiff did not have to perform, i. e., supply the items covered by the calls, it should have refused to do so. It is not proper, says defendant, for plaintiff to recover additional amounts which it deliberately elected to incur. When plaintiff elected to deliver the items and accepted the contract price, it waived any right to obtain more than the contract price. As authority for this line of reasoning, defendant cites, inter alia, Early & Daniel Co. v. United States, 271 U.S. 140, 46 S.Ct. 457, 70 L.Ed. 874 (1926), and Willard, Sutherland & Co. v. United States, 56 Ct.Cl. 413 (1921), aff’d, 262 U.S. 489, 43 S.Ct. 592, 67 L.Ed. 1086 (1923), cases in which the plaintiffs delivered goods to the Government while protesting that they were not bound to do so under the applicable contracts.
The problem with defendant’s argument is that it overlooks the clear mandate of the disputes clause, which reads as follows:
Pending final decision of a dispute hereunder, the Contractor shall proceed diligently with the performance of the contract and in accordance with the Contracting Officer’s decision.
It is the absence of such a clause which distinguishes the earlier cases cited by defendant from the instant case.
This clause protects an important interest of the Government by permitting it to continue to receive needed supplies on schedule,7 despite disputes which *433might arise during performance. It would defeat the salutary purpose of such clauses if contractors who believe that the Government’s instructions are beyond the terms of their contracts must refuse to perform in order to preserve their right to obtain more than the contract price.
Furthermore, defendant’s contentions truly would place plaintiff on the horns of a dilemma because, even if plaintiff chose to refuse performance in order to preserve its extracontraetual rights, it would be doing so at the risk of incurring needless damages for breach of contract should it guess wrong and the Government’s order ultimately be held to fall within the contract terms. Plaintiff should not be subjected to this risk. It did all that could reasonably be expected of it under the circumstances by making timely protest and by indicating its intention to file a claim in accordance with the disputes clause of the contract.8 This served to put the Government on notice that, if it were ultimately held to have demanded goods not required under the contract, it might be required to pay the reasonable value thereof.
In short, the disputes clause in the instant case compelled plaintiff to comply with defendant’s directions, and plaintiff’s delivery of goods under protest did not act to deprive plaintiff of its right to recover beyond the terms of the contract.
In summary, we hold that Call Nos. 8, 9, and 10 were not received by plaintiff within the 18-month period specified in the contract and were thus not issued within that period. Defendant is thus liable to plaintiff for the reasonable value of the items provided by plaintiff in the fulfillment of said calls. Accordingly, plaintiff’s motion for summary judgment is granted, and defendant’s cross-motion is denied.
There is no discussion in the briefs directed to the question of damages, including the issue relating to price discounts, and therefore judgment is entered for plaintiff with the amount of recovery to be determined pursuant to Rule 47(c).