(c) Limitations. Pursuant to 10 U.S.C. 3204(e)(4)(E), the justifications and approvals described in FAR 6.303 and 6.304 are not required if the head of the contracting activity prepares a document that describes the terms of an agreement or treaty or the written directions, such as a Letter of Offer and Acceptance, that have the effect of requiring the use of other than competitive procedures for the acquisition.