Subject to paragraph (7) and except as otherwise provided in paragraph (10)(C), this subsection as in effect in December 1978 shall remain in effect with respect to a primary insurance amount computed under section 415(a) or (d) of this title, as in effect (without regard to the table contained therein) in December 1978 and as amended by section 5117 of the Omnibus Budget Reconciliation Act of 1990, except that a primary insurance amount so computed with respect to an individual who first becomes eligible for an old-age or disability insurance benefit, or dies (before becoming eligible for such a benefit), after December 1978, shall instead be governed by this section as in effect after December 1978. For purposes of the preceding sentence, the phrase “rounded to the next higher multiple of $0.10”, as it appeared in subsection (a)(2)(C) of this section as in effect in December 1978, shall be deemed to read “rounded to the next lower multiple of $0.10”.