ARM 18.15.103
ARM 18.15.103. PAYMENT APPLICATION
Cite as Mont. Admin. R. 18.15.103
(1) Partial payments for a customer's tax liability, including credits, apply as directed by the customer as to account type, period, or otherwise.
(2) If customer direction is not provided, the payment is applied in full to the oldest period first in the following order:
(a) first to tax (dollar for dollar until satisfied);
(b) second to interest (if due); and
(c) third to penalty (if due).