(1)(a) No penalty shall be imposed upon any person who voluntarily reports an underpayment of tax by filing an amended return if the original return is filed on time.

(b) Except as provided in subsection (3) of this section, interest shall not be waived on any additional tax due as reported on any amended return, and such interest shall be computed from the date such tax was due.

(2) The department may in its discretion waive all or any portion of the penalties incurred upon sufficient showing by the taxpayer that the failure to file or pay is not due to negligence, intentional disregard of the law, rules, or regulations, intentional evasion of the tax, or fraud committed with intent to evade the tax or that such penalties should otherwise be waived.

(3) The department may in its discretion waive any and all interest incurred upon sufficient showing by the taxpayer that such interest should be waived.