(a) Additions to tax under section 294(d) of the Internal Revenue Code of 1939. Any addition to the tax under section 294(d) (relating to estimated tax) of the Internal Revenue Code of 1939 shall be computed as if the tax for the year for which the estimate was made were computed with sections 452 and 462 still applicable to such taxable year. For the purpose of the preceding sentence, it is not necessary for the taxpayer actually to have made an election under section 452 or 462; it is only necessary for the taxpayer to have taken such sections into account in estimating its tax liability for the year. Thus, if in determining the amount of estimated tax, the taxpayer computed his estimated tax liability by applying those sections, that portion of any additions to tax under section 294(d) resulting from the repeal of sections 452 and 462 shall be disregarded.

(b) Additions to tax under section 6654. In the case of an underpayment of estimated tax, any additions to the tax under section 6654, with respect to installments due before December 15, 1955, shall be computed without regard to any increase in tax resulting from the repeal of sections 452 and 462. Any additions to the tax with respect to installments due on or after December 15, 1955, shall be imposed in accordance with the applicable provisions of the Code, and as though sections 452 and 462 had not been enacted. Thus, a taxpayer whose declaration of estimated tax was based upon an estimate of his taxable income for the year of the estimate which was determined by taking sections 452 and 462 into account, must file an amended declaration on or before the due date of the next installment of estimated tax due on or after December 15, 1955. Such amended declaration shall reflect an estimate of the tax without the application of such sections. If the taxpayer bases his estimate on the tax for the preceding taxable year under section 6654(d)(1)(A), an amended declaration must be filed on or before the due date of the next installment due on or after December 15, 1955, if the tax for the preceding taxable year is increased as the result of the repeal of sections 452 and 462. Similarly, if the taxpayer bases his estimate on the tax computed under section 6654(d)(1)(B), he must file an amended declaration on or before the due date of the next installment due on or after December 15, 1955, taking into account the repeal of sections 452 and 462 with respect to the preceding taxable year. Any increase in estimated tax shown on an amended declaration filed in accordance with this paragraph must be paid in accordance with section 6153(c).

(c) Estimated tax of corporations. Corporations required to file a declaration of estimated tax under section 6016 for taxable years ending on and after December 31, 1955, shall estimate their tax liability for such year as if sections 452 and 462 had not been enacted. Thus, if the corporation bases its estimated tax liability under section 6655(d) (1) or (2) on its operations for the preceding taxable year, the effect of the repeal of sections 452 and 462 with respect to such year must be taken into account.