In the case of a tax payable in installments, if the taxpayer has paid as an installment
of the tax more than the amount determined to be the correct amount of such installment,
the overpayment shall be credited against the unpaid installments, if any. If the
amount already paid, whether or not on the basis of installments, exceeds the amount
determined to be the correct amount of the tax, the overpayment shall be credited
or refunded as provided in section 6402.
(Aug. 16, 1954, ch. 736, 68A Stat. 791.)
