(a) Installment payments. — The estimated tax of a corporation with respect to which a declaration is required shall be paid as follows:
(1) If the declaration is filed on or before the fifteenth day of the fourth month of the taxable year, the estimated tax shall be paid in four equal installments. The first installment shall be paid at the time of the filing of the declaration, and the second, third and fourth installments shall be paid on the following fifteenth days of the sixth, ninth and twelfth months of the taxable year, respectively.