These regulations apply to every expenditure by a State agency for the acquisition, rental, purchase, or lease of supplies, services, maintenance, construction, construction-related services, architectural services, engineering services, and the lease of real property by the State as lessee. These regulations also apply to certain revenue-producing contracts as set forth in Regulation .03B of this chapter. Each regulation adopted under this title that is in effect on the date of award of any procurement contract, unless otherwise indicated in the regulation, is applicable to the contract. A regulation adopted under this title may not change any right or obligation under a procurement contract in existence before the effective date of the regulation.