(i) The due date for work or services completed by the contractor is the later of the following two events:

(A) The 30th day after the designated billing office receives a proper invoice from the contractor.

(B) The 30th day after Government acceptance of the work or services completed by the contractor.

(1) For a final invoice, when the payment amount is subject to contract settlement actions (e.g., release of claims), acceptance is deemed to occur on the effective date of the settlement.

(2) For the sole purpose of computing an interest penalty that might be due the contractor, Government acceptance is deemed to occur constructively on the 7th day after the contractor completes the work or services in accordance with the terms and conditions of the contract (see also paragraph (c)(2) of this section). If actual acceptance occurs within the constructive acceptance period, the Government must base the determination of an interest penalty on the actual date of acceptance.