(a) In general. If an extension of time under section 6164 is terminated with respect to any amount either (1) by the filing of a new statement by the taxpayer under section 6164(e) extending the time for payment of a lesser amount than was extended in a prior statement, or (2) by action of the district director under section 6164(f) after making an examination of the statement filed by the corporation, no further extension of time may be made under section 6164 with respect to such amount. The time for payment of such amount shall be the dates on which payments would have been required if there had been no extension with respect to such amount and the taxpayer had elected under section 6152(a) to pay the tax in installments.

(b) Example. The provisions of this section may be illustrated by the following example:

Example.Corporation Z, which keeps its books and makes its tax returns on the calendar year basis, filed its income tax return for 1956 on March 15, 1957, showing a tax of $100,000. At the same time it filed a statement under section 6164 extending the time for payment of the entire $100,000 on the basis of an expected net operating loss carryback from 1957. On April 10, 1957, the corporation filed a new statement indicating that the reduction, attributable to the carryback from 1957, in its income tax for 1956, would only be $80,000, and thus terminated the above extension of $20,000. The time for payment of such $20,000 may not be extended again, and such $20,000 is payable as if it were the tax for 1956 and Corporation Z had elected to pay such tax in installments. That is, $10,000 is payable on March 15, 1957, and $10,000 payable on June 17, 1957. Inasmuch as the March 15 date had already passed when the Corporation Z terminated the extension with respect to the $20,000, $10,000 is payable immediately upon such termination, and the other installment of $10,000 is payable on June 17, 1957. This example would also apply if the extension of time for payment of the $20,000 were terminated instead by the district director on April 10, 1957.