1. Contracting officers should evaluate past performance in a commercial item procurement, but it is not mandatory. FAR 12.206.
2. Firm-fixed price commercial item contracts/orders are exempt from CAS. FAR 12.214. CAS Board regulations also exempt labor hour and time & materials commercial item contracts. CASB 9903.201-1(b)(6).
3. Changes to a commercial item contract may be made only by written agreement by the Government and the contractor. FAR 52.212-4(c).