(a) A child support payment is delinquent for the purpose of accrual of interest if the payment is not received before the 31st day after the payment date stated in the order by:
(1) the local registry, Title IV-D registry, or state disbursement unit; or
(2) the obligee or entity specified in the order, if payments are not made through a registry.
(b) If a payment date is not stated in the order, a child support payment is delinquent if payment is not received by the registry or the obligee or entity specified in the order on the date that an amount equal to the support payable for one month becomes past due.