(a) If payments under a construction contract are subject to retainage, any amounts that have been retained during the performance of the contract and that are due to be released to the contractor upon final completion shall be paid within 30 days after final acceptance of the work.

(b) If an owner is not withholding retainage, a contractor or subcontractor may withhold retainage from its subcontractor in accordance with their agreement. The retainage shall be paid within 30 days after final acceptance of the work.

(c) Notwithstanding any contrary agreement, a contractor shall pay to its subcontractors, and each subcontractor shall in turn pay to its subcontractors, within seven days after receipt of the retainage, the full amount due to each such subcontractor.

(d) If an owner, contractor, or subcontractor unreasonably withholds acceptance of the work or fails to pay retainage as required by this section, the owner, contractor, or subcontractor shall be subject to the interest, penalty, and attorney's fees provisions of sections 4002, 4003, and 4007 of this title.

(e) Notwithstanding any provision of this section or an agreement to the contrary, except in the case of a contractor or subcontractor who is both a materialman who delivers materials and is contracted to perform work using those materials, a contractor or subcontractor shall not hold retainage for contracted materials that: