48 CFR §7.202

1. (a)Agencies are required by 10 U.S.C. 3242 and 41 U.S.C. 3310 to procure supplies in such quantity as—
   1. (1)Will result in the total cost and unit cost most advantageous to the Government, where practicable; and
   2. (2)Does not exceed the quantity reasonably expected to be required by the agency.
2. (b)Each solicitation for a contract for supplies is required, if practicable, to include a provision inviting each offeror responding to the solicitation—
   1. (1)To state an opinion on whether the quantity of the supplies proposed to be acquired is economically advantageous to the Government; and
   2. (2)If applicable, to recommend a quantity or quantities which would be more economically advantageous to the Government. Each such recommendation is required to include a quotation of the total price and the unit price for supplies procured in each recommended quantity.