(2) Interest at the rate of two-thirds of one percent per month or fraction of a month shall accrue on any such tax payment not made by the due date (determined without regard to extensions).
(3) A penalty of 10 percent of the tax amount shall be imposed upon any late payment of any such tax, except for a payment made within an extension period as provided in subsection (1) of this section or when the director believes extenuating circumstances justify waiver of the penalty. [1975 c.230 §2; 1980 c.10 §4; 1995 c.786 §7]