Where this subchapter, any provision of another law of the United States (other than the Internal Revenue Code of 1986) relating to or changing the effect of this subchapter, or any regulation issued by the Commissioner of Social Security pursuant thereto provides for a period within which an act is required to be done which affects eligibility for or the amount of any benefit or payment under this subchapter or is necessary to establish or protect any rights under this subchapter, and such period ends on a Saturday, Sunday, or legal holiday, or on any other day all or part of which is declared to be a nonwork day for Federal employees by statute or Executive order, then such act shall be considered as done within such period if it is done on the first day thereafter which is not a Saturday, Sunday, or legal holiday or any other day all or part of which is declared to be a nonwork day for Federal employees by statute or Executive order. For purposes of this subsection, the day on which a period ends shall include the day on which an extension of such period, as authorized by law or by the Commissioner of Social Security pursuant to law, ends. The provisions of this subsection shall not extend the period during which benefits under this subchapter may (pursuant to section
402
(j)(1) or
423
(b) of this title) be paid for months prior to the day application for such benefits is filed, or during which an application for benefits under this subchapter may (pursuant to section
402
(j)(2) or
423
(b) of this title) be accepted as such.