Any state contract for which an agency is a party with probable fees, including reimbursable expenses and amendments, less than the threshold amount or amounts established by the Contracting and Purchasing Advisory Council pursuant to § 6913 of this title for the completed job shall be excluded from all other portions of this subchapter. Agencies may, alternately, at their discretion, procure services which include materiel other than professional services in accordance with § 6924 of this title.