If a taxpayer remits a payment on or before the due date, but the payment is insufficient to discharge the tax liability, the entire amount of such payment shall apply to the tax. Any penalty or interest subsequently assessed shall be based on the unpaid portion of the tax.
If the department determines there is additional tax due from a taxpayer, interest and penalty shall accrue on that amount from the date the tax should have been reported and paid.
This rule is intended to implement Iowa Code sections 452A.54, 452A.55, 452A.60, 452A.61, 452A.63, 452A.64, and 452A.65.
Iowa Admin. Code r. 761-505.4