; and (ii) a mother's and father's insurance benefit under section 202(g). . (b) Treatment of disabled beneficiaries Section 215(a) of such Act (as amended by subsection (a)) is amended further by adding at the end the following new paragraph: (9) (A) Notwithstanding the preceding provisions of this subsection, in the case of an individual who has or has had a period of disability and who initially becomes eligible for old-age insurance benefits or who dies (before becoming eligible for such benefits) in any calendar year in or after 2027, the primary insurance amount of such individual shall be the sum of— (i) the amount determined under subparagraph (B); and (ii) the product derived by multiplying— (I) the excess of the amount determined under subparagraph (C) over the amount determined under subparagraph (B); by (II) the adjustment factor for such individual determined under subparagraph (D). (B) The amount determined under this subparagraph is the amount of such individual's primary insurance amount as determined under this section without regard to this paragraph. (C) The amount determined under this subparagraph is the amount of such individual's primary insurance amount as determined under this section as in effect with respect to individuals becoming eligible for old-age or disability insurance benefits under section 202(a) on the date of the enactment of the Social Security Solvency and Sustainability Act . (D) The adjustment factor determined under this subparagraph for any individual is the ratio (not greater than 1) of— (i) the total number of months during which such individual is under a disability (as defined in section 223(d)) during the period beginning on the date the individual attains age 22 and ending on the first day of such individual's first month of eligibility for old-age insurance benefits under section 202(a) (or, if earlier, the month of such individual's death)