1. (a) A taxpayer applying for an automatic six-month extension for filing its tax return must pay, on or before the date its return is required to be filed, without regard to any extension of time, its properly estimated tax. The estimated tax paid, or balance thereof, will be deemed properly estimated if the tax paid is either:

   1. (1) not less than 90 percent of the tax as finally determined; or
   2. (2) not less than the tax shown on the taxpayer's return for the preceding taxable year, if such preceding year was a taxable year of 12 months.

Tax Law, § 1463(b)