Iowa Admin. Code r. 701-254.6
The department shall have the right and duty to examine or cause to be examined the books, records, memoranda or documents of a taxpayer for the purpose of verifying the correctness of a return or report filed or determining the tax liability of any taxpayer under Iowa Code chapter 453A.
When it is determined, upon audit, that any person dealing in cigarettes owes additional tax, the costs of the audit are assessed against such person as additional penalty.
The department may, at any time within the period prescribed for assessment or refund adjustment, make a supplemental assessment or refund adjustment whenever it is ascertained that any assessment or refund adjustment is imperfect or incomplete in any respect.
If an assessment or refund adjustment is appealed (protested under rule 701-7.8 (17A)) and is resolved whether by informal proceedings or by adjudication, the department and the taxpayer are precluded from making a supplemental assessment or refund adjustment concerning the same issue involved in such appeal for the same tax period unless there is a showing of mathematical or clerical error or a showing of fraud or misrepresentation.
This rule is intended to implement Iowa Code section 453A.30.
Iowa Admin. Code r. 701-254.6