Tax not paid by the statutory due date of the return is subject to 1 percent interest and 5 percent late filing and/or 1/2 of 1 percent late payment penalty per month, or fraction thereof. Interest accrues until the tax due has been paid in full; the combined total of late filing and late payment penalty cannot exceed 25 percent of the tax shown on the return. An extension of time for filing the return does not extend the date for making the payment. Additional penalties may apply as follows:
