A. The declaration of estimated tax shall be filed as follows: If the requirements of subsection A of § 58.1-500 are first met:
1. Before the first day of the fourth month of the taxable year, the declaration shall be filed on or before the fifteenth day of the fourth month of the taxable year.
2. After the last day of the third month and before the first day of the sixth month of the taxable year, the declaration shall be filed on or before the fifteenth day of the sixth month of the taxable year.
3. After the last day of the fifth month and before the first day of the ninth month of the taxable year, the declaration shall be filed on or before the fifteenth day of the ninth month of the taxable year.
4. After the last day of the eighth month and before the first day of the twelfth month of the taxable year, the declaration shall be filed on or before the fifteenth day of the twelfth month of the taxable year.
B. An amendment of a declaration may be filed in any interval between installment dates prescribed for the taxable year, but only one amendment may be filed in each such interval.
C. The application of this section to taxable years of less than twelve months shall be in accordance with regulations prescribed by the Tax Commissioner.