D.C. Mun. Regs. tit. 27, r. 27-2304
A fixed-price supply contract may authorize District acceptance of a variation in the quantity of items if the variation is caused by conditions of loading, shipping, packing, or by allowances in manufacturing processes.
Except as provided in § 2304.3 of this chapter, any permissible variation shall be stated as a percentage. The variation may be an increase, a decrease, or a combination of both.
Contracts for perishable food items may use other applicable terms of variations in quantity.
There shall be no standard or usual variation percentage.
The overrun or under run permitted in each contract shall be based upon the normal commercial practices of a particular industry for a particular item, and the permitted percentage shall be no larger than is necessary to afford a contractor reasonable protection.
Contractors shall be responsible for delivery of the specified quantity of items in a fixed-price contract, within allowable variations, if any.
D.C. Mun. Regs. tit. 27, r. 27-2304