1. An additional assessment shall be a final decision of the director of revenue. Notwithstanding the provisions of section 621.050 to the contrary, an additional assessment may be appealed to the administrative hearing commission within sixty days after the date the assessment is delivered in person or is sent by certified mail, whichever is earlier.

2. Within sixty days after the date on which an additional assessment is delivered in person or is sent by certified mail, whichever is earlier, the taxpayer may request an informal review of the assessment by the director of revenue. The informal review shall not affect the time within which the taxpayer may appeal the assessment to the administrative hearing commission and any such appeal must be filed within sixty days after the date the assessment is delivered in person or is sent by certified mail, whichever is earlier. If such an informal review is requested by a taxpayer, the director of revenue shall informally review the assessment. The informal review shall not require findings of fact or conclusions of law. If the taxpayer proves to the director’s satisfaction that the assessment is incorrect, the assessment shall be cancelled and a revised assessment may be made against the taxpayer for the same period, notwithstanding the provisions of section 144.220 to the contrary.

3. The taxpayer may request and the director may enter into a payment agreement with any taxpayer against which an assessment has been made, if the director determines that such agreement is in the best interest of the state.