(a) Except as provided in Code Section 13-11-5, if a periodic or final payment to a contractor is delayed by more than 15 days or if a periodic or final payment to a subcontractor is delayed more than ten days after receipt of periodic or final payment by the contractor or subcontractor, the owner, contractor, or subcontractor, as the case may be, shall pay his or her contractor or subcontractor interest, beginning on the day following the due date, at the rate of 1 percent per month or a pro rata fraction thereof on the unpaid balance as may be due. However, no interest is due unless the person being charged interest has been notified of the provision of this Code section at the time the request for payment is made. Acceptance of progress payments or final payment shall release all claims for interest on said payments.
(b) Nothing in this chapter shall prohibit owners, contractors, and subcontractors from agreeing by contract to rates of interest, payment periods, and contract and subcontract terms different from those stipulated in this Code section, and in this event, these contractual provisions shall control. In case of a willful breach of the contract provisions as to the time of payment, the interest rate specified in this Code section shall apply.