10 U.S.C. 2308 authorizes DoD to use funds available for the acquisition of an end item to acquire a higher quantity of the end item than the quantity specified in a law providing for the funding of that acquisition, if the head of an agency determines that—

(a) The agency has an established requirement for the end item that is expected to remain substantially unchanged throughout the period of the acquisition;

(b) It is possible to acquire the higher quantity of the end item without additional funding because of production efficiencies or other cost reductions;

(c) The amount of funds used for the acquisition of the higher quantity of the end item will not exceed the amount provided under that law for the acquisition of the end item; and

(d) The amount provided under that law for the acquisition of the end item is sufficient to ensure that each unit of the end item acquired within the higher quantity is fully funded as a complete end item.