The second contention of appellant as a basis for relief is that although the article submitted for approval was manufactured in accordance with the contract requirements, the Government refused to approve it because the Government was testing in accordance with Revision A instead of the contract specifications. As a final contention, appellant argues that the "risk" of acquisition of materials and production imposed on the contractor by subparagraph (g) applies only with respect to "progress payments" and does not apply to cases where the Government terminates the contract for convenience. FURTHER FINDINGS OF FACT AND DECISION We shall consider first appellant's contention that the Government waived the clause entitled (First Article Approval - Contractor Testing (Aug. 1965)." In support of this contention appellant first argues that the Government impressed appellant with the urgency of the contract and thereby waived the clause. Assuming the Government did as contended impress upon appellant the urgency of the contract, we do not see how this fact alone could constitute a waiver. In any event, in the instant case appellant has not proved that the Government by its actions conveyed an impression of urgency or in any way suggested or directed appellant to acquire production material and enter into production prior to receipt of first article approval. Appellant calls to our attention two letters written by the contracting officer dated 18 September 1967 and 12 September 1967 (Rule 4 Document 3 Encls. 1 and 3), and a letter written by appellant dated 15 February 1967 (Rule 4 Document 3 Encls. 2). The 18 September 1967 letter was written to "All LOGIC Contractors," and merely advised all such contractors of the change in program name from "LOGIC" to "VIP." The 12 September 1967 letter was written primarily to advise appellant that the second submission of the first article test report was not approved. This letter further indicated the Government's concern with respect to appellant's ability to meet the contract requirements and requested to be advised if appellant could not correct the deficiencies so that the item could be procured from a qualified source to preclude a critical supply problem. There is nothing in the language or tenor of these two letters which could constitute a basis for our holding that the Government waived the provisions of the First Article clause. As to the appellant's 15 Feburary 1967 letter, it appears to be nothing more than a status report and an expression of optimism on the part of appellant with respect to its ability to meet or exceed the delivery schedule. We do not construe this letter as a basis for holding that the provisions of the First Article Test clause was waived. Next we will consider appellant's claim that the excessive length of time spent by the Government in evaluating the first article test report without granting an extension of time as an excusable delay constituted a waiver. To the extent pertinent the First Article Approval clause provides as follows: "(b) *** The Contracting Officer shall, by written notice to the Contractor within fifteen (15) calendar days after receipt of such test report by the Government, approve, conditionally approve, or disapprove such first article. *** "(f) In the event the Contracting Officer Clearly The first test report was submitted on 13 April 1967 and disapproved by letter dated 12 June 1967. The second test report was submitted on 27 July 1967 and disapproved by letter dated 12 September 1967. the written notice to the contractor was not within the fifteen (15) calendar days required by subparagraph (b). Appellant's remedy for the Government's failure to approve or disapprove the test report within the 15 days is clearly set out in subparagraph (f). We hold that the Government's failure to evaluate the first article test report within the time provided for in subparagraph (b) does not constitute a waiver of the entire clause. We shall now consider appellant's contention of waiver on the grounds that the Government insisted upon evaluating actual samples instead of first article reports thereby imposing a greater risk upon appellant that the first article would be disapproved. Appellant made this allegation in its 30 August 1968 letter (Rule 4 Document 3) to the contracting officer, and has not submitted any evidence in support thereof. The Government in its answer states that it did not insist upon any inspection of samples. An allegation of a disputed fact does not prove it. Evidence is required to prove such an allegation. William G. Knight d/b/a K & E Bus Line, ASBCA No. 10783, 17 September 1965, 65-2 BCA par. 5099. Appellant has not proved that the Government insisted upon evaluating actual samples. Consideration will now be given to appellant's contention that the Government refused to give formal first article approval even though the articles were manufactured in accordance with the contract requirements because the Government tested to Revision A rather than the contract specifications. The Government denies that the item produced by appellant and tested complied with the requirements of the contract. The Government further denies that it tested to Revision A instead of the contract specifications and drawings in evaluating appellant's test reports. In support of its contention that the first article met the contract requirements appellant states, "(Note that the fact this contract was terminated for convenience is prima facie evidence that our first article met all contract requirements.)" Appellant submitted no other evidence to prove that the item which it manufactured met the contract requirements or that the Government tested to Revision A. We cannot agree under the facts and circumstances here present that the issuance of a termination for convenience is prima facie evidence that the first article met all the contract requirements. At the time the contract was terminated appellant had submitted two test reports, neither of which had been approved by the Government. Appellant acknowledged that it was delinquent and offered $500 as consideration for an extension of time to submit another test report. The Government accepted appellant's offer and issued Modification P001 which extended the delivery date for the first article test report to 60 days after the effective date of the modification, which was 8 January 1968. Therefore, on 12 December 1967, the date the contract was terminated, appellant had not submitted an acceptable test report but still had until 8 January 1968 to do so. Under such circumstances if the Government no longer wanted appellant to furnish the item covered by the contract it could do nothing other than terminate contract for convenience. Appellant has not proved that it manufactured an item which satisfied the contract requirements, or that the Government tested to Revision A. Finally, we consider appellant's contention that subparagraph (g) applies only to progress payments and does not apply to termination for convenience. The same contention was made and considered by this Board in the appeal of Precision Switch Corporation, ASBCA No. 13986, 25 November 1969, 69-2 BCA par. In that appeal, as in the appeal before us, the contracting officer refused to allow in a termination claim costs associated with production. The appellant argued that the clause applied only to progress payments, not to the Termination for Convenience clause, and that the contracting officer could not refuse to allow costs associated with production. In the Precision appeal the Board held: "'*** We have examined the clause and, in "Prior to approval of the first article, the Here too appellant is entitled to recover only costs allocable to the first article. The disallowance of costs for production quantities is correct. The disallowance of costs for production quantities is correct. LYKES BROS. STEAMSHIP CO., INC. v. THE UNITED STATES ON PLAINTIFF'S REQUEST FOR REVIEW OF COMMISSIONER'S ORDER DENYING MOTION TO MODIFY PRETRIAL ORDER Cowen, Chief Judge, delivered the opinion of the court: This case is one of many recently transferred from the United States Tax Court pursuant to Public Law 92-41 & 3, 85 Stat. 97, 98 (1971). That statute amended the Renegotiation Act of 1951, 50 U.S.C. App. 81211, et seq. (1970), to vest this court with exclusive jurisdiction to redetermine excessive profits determined by the Renegotiation Board. The case is presently before the court on plaintiff's request for review of a pretrial order by Commissioner George Willi. The order places upon plaintiff the burdens of proceeding with the evidence and of persuading this court that it "did not realize excessive profits in ay amount greater than it concedes." As explained below, we have decided to apply a different evidentiary rule. Accordingly, we vacate the commissioner's order and remand the case for further proceedings consistent with this opinion. I On November 2, 1971, the commissioner filed in the present case a pretrial order which directed plaintiff, and thereafter defendant, to file certain specified submissions and responses aimed at more fully delineating the issues to be tried. The order directed that the first submission, by plaintiff, include plaintiff's version of its income statement, segregating its renegotiable from its nonrenegotiable business for the year involved, as well as certain balance sheet information. The order further required that plaintiff's initial submission set forth each proposition of law and related proposition of fact, together with an explanation of its evidentiary basis, upon which plaintiff intends to rely to prove that its profits were not excessive. The required propositions would include specific references to the so-called "statutory factors," 50 U.S.C. App. § 1213 (e) (1970), which must be considered in determining excessive profits. Plaintiff did not object to the requirement that it proceed first by submitting its income statement and balance sheet data, just as it had done in the proceedings before the Renegotiation Board. However, plaintiff moved that the commissioner delete from his order the requirement that plaintiff proceed first with submissions to the effect that it realized no excessive profits. Plaintiff's position was that such submissions should be made by way of reply to defendant's submissions. On December 17, 1971, the commissioner issued another order, denying plaintiff's motion and placing upon it the burden of going forward, as well as the burden of persuasion, on the main issue. It is plaintiff's contention here, as it was before the commissioner, that his orders give legal effect and a presumption of validity to the decision of the Renegotiation Board, a result which plaintiff asserts is wholly inconsistent with the statutory directive that the suit here "shall not be treated as a proceeding to review the determination of the Board, but shall be treated as a proceeding de novo." 50 U.S.C. App #1218 (1970), as amended, Pub. L. No. 92-41, 85 Stat. 97 (1971). In dismissing plaintiff's contention that the burdens of persuasion and proceeding with the evidence should realistically be placed upon the defendant, the commissioner relied on the fact that Congress has never chosen to override the Tax Court's consistent practice of imposing on the contractor, except in certain limited circumstances, both evidentiary burdens. Noting isolated language from the congressional committee reports accompanying the legislation which transferred jurisdiction in renegotiation cases to this |