48 CFR § 1436.571
Additive and deductive items
November 17, 2020
If it appears that funds available for a construction project may be insufficient for all the desired features, the CO may provide in the solicitation for a base bid item covering the work as specified and for one or more additive or deductive bid items which add or omit specified features of the work in a stated order of priority. Such solicitations shall include a provision substantially as set forth in 1452.236-71, and the low bidder and the bid items to be awarded shall be determined as provided in the provision.