1. (a) If the taxpayer files its report for the calendar year on or before February 15th of the succeeding calendar year (or if the taxpayer is on a fiscal-year basis, on or before the 15th day of the second month succeeding the taxable year) and pays therewith the balance, if any, of the full amount of the tax shown to be due on the report:

   1. (1) Such report will be considered to be its declaration if no declaration was required to be filed on or before the 15th day of the ninth month of the calendar year or fiscal year for which the tax was imposed, but a declaration was required to be filed on or before the 15th day of the 12th month of the calendar year or fiscal year pursuant to section 7-2.3 of this Subpart.

   2. (2) Such report will be considered as the amendment permitted by section 7-2.4 of this Subpart to be filed on or before the 15th day of the 12th month of the calendar year or fiscal year if the tax shown on the report is greater than the estimate shown on the declaration previously made.

      Example 1:

      A taxpayer which reports on the basis of a calendar year first meets the requirement for making a declaration of estimated tax on September 5, 1981. The taxpayer may satisfy the requirement for making a declaration of estimated tax by making and filing its report for taxable year 1981 on or before February 15, 1982, and paying, at the time of filing, the balance, if any, of the full amount of tax shown to be payable. The report will be treated as the declaration required to be filed on or before December 15, 1981.

      Example 2:

      The taxpayer makes and files, on or before September 15, 1981, a timely declaration of estimated tax for such year, and on or before February 15, 1982 files its 1981 tax report and pays the balance, if any, of the full amount of tax shown to be payable. If the taxpayer's report shows the tax to be greater than the estimated tax shown on the declaration, the report will be treated as the amended declaration permitted to be filed on or before December 15, 1981.

2. (b) The filing of a declaration or amended declaration or the payment of the last installment of estimated tax on December 15th, or the filing of a report by February 15th of the succeeding calender year (or if on a fiscal-year basis, on the 15th day of the 12th month of the current fiscal year and the 15th day of the second month of the succeeding fiscal year), will not relieve the taxpayer of the additional charge for underpayment of installments if it failed to pay its estimated tax which was due earlier in its taxable year.

Tax Law, § 213-a(e) and (f)