(a) Any person who fails to file a report when due shall pay a fee of $10.00 as partial compensation for the added administrative costs.
(b) In addition to the fee prescribed in subsection (a) of this section, any person who fails to pay any tax when due shall pay in addition to the tax interest calculated at one and one-half percent per month on the tax from the due date, until paid. In addition, if the taxpayer fails to pay the tax liability in full within 30 days, a penalty equal to five percent of the outstanding tax liability for each month or portion of a month shall be paid; provided, however, that in no event shall the amount of the penalty imposed exceed 25 percent of the tax liability unpaid on the prescribed date of payment. The Commissioner may remit all or any part of the penalty if he or she is satisfied that the delay was excusable.