1. In case of failure to file any return required under sections 144.010 to 144.525 on or before the date prescribed therefor, determined with regard to any extension of time for making a return, unless it is shown that such failure is due to reasonable cause and not the result of willful neglect, evasion or fraudulent intent, there shall be added to the amount required to be shown as tax on such return five percent of the amount of such tax if the failure is not for more than one month, with an additional five percent for each additional month or fraction thereof during which such failure continues, not exceeding twenty-five percent in the aggregate, except that when the gross sales tax exceeds two hundred fifty dollars in any one month, requiring the taxpayer to file a monthly return, there shall be no late penalty assessed for the first month in which the return is due. For purposes of this section, the amount of tax required to be shown on the return shall be reduced by the amount of any part of the tax which is paid on or before the date prescribed for payment of the tax.

2. In case of failure to pay the full amount of tax required under sections 144.010 to 144.525 on or before the date prescribed therefor, determined with regard to any extension of time for payment, unless it is shown that such failure is due to reasonable cause and not the result of willful neglect, evasion or fraudulent intent, there shall be added to the tax an amount equal to five percent of the deficiency. If additions to tax are assessed under authority of this subsection, additions to tax may not be assessed by the director under authority of subsection 3 of this section.

3. In the case of failure to pay the full amount of tax required under sections 144.010 to 144.525 on or before the date prescribed therefor, determined with regard to any extension of time for payment, due to negligence or intentional disregard of rules and regulations, but without intent to defraud, there shall be added to the tax an amount equal to five percent of the deficiency. The director shall, upon request by a taxpayer, apprise the taxpayer of the factual basis for the finding of negligence, or the specific rules or regulations disregarded if the director assesses a penalty under this subsection. Rules or regulations which have been determined to be inconsistent with the laws of this state, by either the courts of this state or the administrative hearing commission, may not be cited as the basis for an addition to tax under this section. If additions to tax are assessed under authority of this subsection, additions to tax may not be assessed by the director under authority of subsection 2 of this section.

4. Except in cases of fraud or evasion, if a person neglects or refuses to make a return and payment as required by sections 144.010 to 144.525, the director of revenue shall make an estimate based upon any information in his possession or that may come into his possession of the amount of the gross receipts of the delinquent for the period in respect to which he failed to make return and payment, and upon the basis of said estimated amount compute and assess the tax payable by the delinquent; such estimate may be reconstructed for that period of time for which the tax may be collected as prescribed by law.

5. Promptly thereafter, the director of revenue shall give to the delinquent written notice of such estimated assessment, the notice to be served personally or by certified or registered mail at his or its last known address.

6. The penalties and additions to tax authorized under this section shall be in addition to the interest provided for in this chapter.

7. The penalties or additions to tax authorized pursuant to this section for all taxes on motor vehicles, trailers, motorcycles, mopeds, motortricycles, boats, and outboard motors pursuant to subdivision (1) of subsection 1 of section 144.020 and section 144.440 shall be doubled as of November 1, 2003.