For the purpose of determining average indexed monthly earnings, average monthly wage, and quarters of coverage in the case of any individual who elects the option described in clause (ii) or (iv) in the matter following section
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(a)(16) of this title for any taxable year that does not begin with or during a particular calendar year and end with or during such year, the self-employment income of such individual deemed to be derived during such taxable year shall be allocated to the two calendar years, portions of which are included within such taxable year, in the same proportion to the total of such deemed self-employment income as the sum of the amounts applicable under section
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(d) of this title for the calendar quarters ending with or within each such calendar year bears to the lower limit for such taxable year specified in section
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(k)(1) of this title.