Section 30B:13 - Increase of services or supplies specified in contractThe governmental body may increase the quantity of supplies or services or both specified in a contract provided:
(1) the unit prices remain the same or less;(2) the procurement officer has specified in writing that an increase is necessary to fulfill the actual needs of the governmental body and is more economical and practical than awarding another contract;(3) the parties agree to the increase in writing; and(4) the increase in quantity, in any contract except a contract for the purchase of gasoline, fuel oil, or road salt, does not exceed ten percent.Mass. Gen. Laws ch. 30B, § 13