Upon approval by the office of a state set-aside assignment, the fuel allocation officer shall issue a written order authorizing the assignment and shall serve it on the prime supplier and, where applicable, the local distributor of the prime supplier, from whose set-aside the assigned product is to be drawn. An order issued by the office under this section is effective upon issuance, unless stayed, modified, suspended or rescinded, and represents a call on the prime supplier's set-aside volume for the month of issuance, even if delivery of the product cannot be made until the following month.