If a widow or widower of a deceased employee is entitled to an annuity under
section 231a(a)(1) of this title and if either such widow or widower or such deceased employee will have completed 10 years of service prior to
January 1, 1975, the amount of the annuity of such widow or widower under subdivisions (1) through (3) of this subsection shall be increased by an amount equal to the amount, if any, by which (A) the widow’s or widower’s insurance annuity to which such widow or widower would have been entitled, upon attaining age 65, under section 5(a) of the Railroad Retirement Act of 1937 [
45 U.S.C. 228e(a)] as in effect on
December 31, 1974 (without regard to the proviso of that section or the first proviso of section 3(e) of that Act [
45 U.S.C. 228c(e)] on the basis of the deceased employee’s remuneration and service prior to
January 1, 1975, increased by the same percentage, or percentages, as widow’s and widower’s insurance benefits under section 202 of the Social Security Act [
42 U.S.C. 402] are increased during the period from
January 1, 1975, to the later of the date on which such widow’s or widower’s annuity under
section 231a(a)(1) of this title began to accrue or the date on which such widow’s or widower’s annuity under
section 231a(d)(1) of this title began to accrue, exceeds (B) the total of the annuity amounts to which such widow or widower was entitled (after any reductions pursuant to subsection (i)(2) of this section but before any deductions on account of work) under the preceding provisions of this subsection, subsection (f) of this section, and the amount determined under subsection (h) of this section, before the proviso, as of the later of the date on which such widow’s or widower’s annuity under
section 231a(a)(1) of this title began to accrue or the date on which such widow’s or widower’s annuity under
section 231a(d)(1) of this title began to accrue. If a widow or widower of a deceased employee is not entitled to an annuity under
section 231a(a)(1) of this title or to an old-age insurance benefit or a disability insurance benefit under the Social Security Act [
42 U.S.C. 301 et seq.], the amount of the annuity to which such widow or widower is entitled under this subsection shall not be less than an amount which would cause the total of the annuity amounts to which such widow or widower is entitled (before any deductions on account of work) under this subsection and subsection (f)(1) of this section to equal the total of the annuity amounts to which such widow or widower was entitled (or would have been entitled except for the provisions of sections 231a(e) and 231a(f) of this title) as a spouse under subsections (a), (b), and (e) of this section (after any reduction on account of age) in the month preceding the employee’s death. If a widow or widower of a deceased employee is entitled to an annuity under
section 231a(a)(1) of this title or to an old-age insurance benefit or a disability insurance benefit under the Social Security Act, the amount of the annuity to which such widow or widower is entitled under this subsection shall not be less than an amount which would cause (A) the total of the annuity amounts to which such widow or widower is entitled (after any reductions pursuant to section 202(k) or 202(q) of the Social Security Act or subsection (i)(2) of this section but before any deductions on account of work) under this subsection and subsection (f) of this section to equal (B)(i) the total of the annuity amounts, if any, to which such widow or widower was entitled (or would have been entitled except for the provisions of sections 231a(e) and 231a(f) of this title) as a spouse under subsections (a), (b), and (e) of this section (after any reduction on account of age) in the month preceding the employee’s death less (ii), if such widow or widower is entitled to an old-age insurance benefit or a disability insurance benefit under the Social Security Act but was not entitled to such a benefit in the month preceding the employee’s death, the amount by which the annuity amount payable under subsection (a) of this section to such widow or widower as a spouse in the month preceding the employee’s death would have been reduced by reason of section 202(k) or 202(q) of the Social Security Act if such widow or widower had been entitled to an old-age insurance benefit or a disability insurance benefit under the Social Security Act in the month preceding the employee’s death in an amount equal to the amount of such benefit at the time such benefit first began to accrue to such widow or widower.