No action may be brought by a state public body on any architectural or engineering services contract, including architectural or engineering services contracts governed by Chapter 43.1 (§ 2.2-4378 et seq.), unless such action is brought within 15 years after completion of the contract. For the purposes of this section, completion of the contract is the final payment to the contractor pursuant to the terms of the contract. However, if the architectural or engineering services are for a construction project for which a final certificate of occupancy or written final acceptance of the project is issued prior to final payment, the 15-year period to bring an action shall commence no later than 12 months from the date of the certificate of occupancy or written final acceptance of the project. In no case shall such action be brought more than five years after written notice by the state public body to the contractor of a defect or breach giving rise to the cause of action. The state public body shall not unreasonably delay written notice to the contractor.