(1) Returns and Payments of Estimated Tax.

(a) Each person whose net profits are subject to the tax imposed by this Chapter shall be required to file returns and pay estimated tax on account of the net profits due for the current taxable year.

(2) For the purposes of this Chapter, the term "estimated tax" means the amount of net profits tax which a person calculated to be his tax due under this Chapter for the preceding taxable year, after giving effect to the tax credit provided in Section 19-1506.^[220]

(3) Calendar Year Taxpayers.

(a) Returns and payments of estimated tax for taxable years beginning after December 31, 1984 shall be due and payable as follows:

(.1) The first installment of one-fourth (¼) of the estimated tax shall be due and payable on or before April 15 of the taxable year.

(.2) The second installment of one-fourth (¼) of the estimated tax shall be due and payable on or before June 15 of the taxable year.

(4) Fiscal Year Taxpayers.

(a) Persons who report net income for a fiscal year period other than a calendar year shall make returns and payments of estimated tax for taxable years beginning after December 31, 1984 as follows:

(.1) The first installment of one-fourth (¼) of the estimated tax shall be due and payable within three and one-half (3½) months after the beginning of the taxable fiscal year.

(.2) The second installment of one-fourth (¼) of the estimated tax shall be due and payable within five and one-half (5½) months after the beginning of the taxable fiscal year.

(5) Credits for Excessive Estimated Payments.

(a) Any estimated payments which exceed a person's tax liability for the taxable year shall be applied as a credit against the estimated tax for the following taxable year, to the extent of the estimated tax due for the following taxable year.

(b) The amount of any estimated payments which exceed the estimated tax for the following year shall be refunded to the taxpayer.

(6) Provisions not Applicable. The provisions of Section 19-1505 shall not be applicable to a person for a taxable year if:
(a) Such person was not engaged in business in the preceding taxable year; or

(b) Such person's net profits tax liability for the preceding taxable year does not exceed $100; or

(c) Such person terminated his business activity prior to the due date of the net profits tax return for the preceding taxable year.

(7) Any person who terminates his business activity prior to the due date of any estimated payment shall not be required to make any additional estimated payments for that taxable year.