2 Notice of assessment, supplemental assessments and refund adjustments. If after

following the procedure outlined in subrule 305.1(2) no agreement is reached, and the taxpayer does not pay the amount determined to be correct, a notice of assessment shall be sent to the taxpayer by mail. If the period in which the correct amount of tax can be determined is nearly at an end, either a notice of assessment without compliance with subrule 305.1(2) or a jeopardy assessment may be issued. All notices of assessment shall bear the signature of the director. 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 (under rule 701—7.9(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 the appeal for the same tax period unless there is a showing of mathematical or clerical error or a showing of fraud or misrepresentation. Nothing in this rule shall prevent the making of an assessment or refund adjustment for the purpose of taking into account the impact upon Iowa net income of federal audit adjustments. This rule is intended to implement Iowa Code sections 422.25 and 422.30. [ARC 0251C, IAB 8/8/12, effective 9/12/12; Editorial change: IAC Supplement 11/2/22; Editorial change: IAC Supplement 10/18/23]