(A) If an individual has wages or self-employment income for a year after 1978 for any part of which he is entitled to old-age or disability insurance benefits, the Commissioner of Social Security shall, at such time or times and within such period as the Commissioner may by regulation prescribe, recompute the individual’s primary insurance amount for that year.

(B) For the purpose of applying subparagraph (A) of subsection (a)(1) to the average indexed monthly earnings of an individual to whom that subsection applies and who receives a recomputation under this paragraph, there shall be used, in lieu of the amounts established by subsection (a)(1)(B) for purposes of clauses (i) and (ii) of subsection (a)(1)(A), the amounts so established that were (or, in the case of an individual described in subsection (a)(4)(B), would have been) used in the computation of such individual’s primary insurance amount prior to the application of this subsection.

(C) A recomputation of any individual’s primary insurance amount under this paragraph shall be made as provided in subsection (a)(1) as though the year with respect to which it is made is the last year of the period specified in subsection (b)(2)(B)(ii); and subsection (b)(3)(A) shall apply with respect to any such recomputation as it applied in the computation of such individual’s primary insurance amount prior to the application of this subsection.

(D) A recomputation under this paragraph with respect to any year shall be effective— (i) in the case of an individual who did not die in that year, for monthly benefits beginning with benefits for January of the following year; or (ii) in the case of an individual who died in that year, for monthly benefits beginning with benefits for the month in which he died.