1.  Definitions.  As used in this section, unless the context otherwise indicates, the following terms have the following meanings.  

2.  Requirement to pay estimated tax.  A person subject to taxation under this chapter shall make payment of estimated tax as required by this chapter. The requirement to make estimated tax payments is waived if:  

3.  Amount of estimated tax to be paid.  A person required to make payment of estimated tax under this chapter is liable for an estimated tax that is no less than the lesser of:  

4.  Amount of installment.  The amount of estimated tax to be paid in a tax year by a taxpayer is to be paid in installments by the dates established in this section. The amount of the estimated tax is to be paid in 4 equal installments unless the taxpayer establishes by adequate record the actual distribution of tax liability and allowable credits, or both, in which case the amount of the installment payments must be adjusted accordingly and be determined in accordance with the portion of the taxpayer's estimated tax liability applicable to that portion of the taxpayer's tax year, completed by the close of the month preceding the installment's due date, less estimated tax payments already made for the tax year.  

5.  Due dates for estimated tax installments.  An estimated tax installment payment calculated pursuant to subsection 4 is due the 15th day of the 4th, 6th, 9th and 13th month following the beginning of the taxpayer's tax year.  

6.  Penalty.  A penalty accrues automatically on underpayments of the required installment amount pursuant to subsection 4 for the period of underpayment at the interest rate provided pursuant to section 186. For cause, the assessor may waive or abate all or any part of the penalty.  

7.  Short taxable year.  For a tax year of less than 12 months, the estimated tax must be paid in full by the 15th day of the last month of the tax year. For payment dates falling within the short taxable year, payment must be made as provided in subsection 5.  

8.  Installments paid in advance.  At the taxpayer's election, an installment of estimated tax required pursuant to subsection 4 may be paid prior to the date prescribed for its payment.