The chief purchasing officer shall issue regulations providing for as many alternative methods of management of construction contracting as he or she may determine to be feasible, setting forth criteria to be used in determining which method of management of construction is to be used for a particular project, and granting to the purchasing agent, or the purchasing agency responsible for carrying out the construction project, the discretion to select the appropriate method of construction contracting for a particular project, provided, however, that the chief purchasing officer shall execute and include in the contract file a written statement setting forth the facts which led to the selection of a particular method of management of construction contracting in each instance.