(a) In AS 36.90.210 - 36.90.290,
(1) a payment is considered to be made when mailed or personally delivered to the party being paid;
(2) a payment is considered to be received when it is endorsed for payment, if it is a check;
(3) an invoice is considered to be received when it is date-stamped or otherwise marked as delivered: if the invoice is not date-stamped or otherwise marked as delivered, the date of the invoice is considered to be the date when the invoice is received.
(b) A political subdivision that receives a state grant for a public construction or public works project may use money from the state grant to pay the interest under AS 36.90.200 - 36.90.290.