RSA 78-C:4 Payment of Tax.

I. One-third of the taxpayer's estimated tax on refined petroleum products for the subsequent taxable period is due and payable at the time the taxpayer files the declaration required in RSA 78-C:3, II; 1/3 is due and payable one month thereafter; and 1/3 is due and payable 2 months thereafter. If the return required by RSA 78-C:3, I, shows an additional amount to be due, such additional amount is due and payable at the time the return is filed. If such return shows an overpayment of the tax due, the commissioner shall allow the taxpayer a credit against a subsequent payment or payments due, to the extent of the overpayment.
II. Any person who produces refined petroleum products who fails to make payment when due shall, in addition, pay a late payment charge equal to 10 percen