§ 511. Coordination with social security benefits. a. A member's service retirement or disability benefit shall be reduced by fifty percent of the primary social security retirement or disability benefit, as the case may be, commencing at (i) age sixty-two, with respect to service retirement benefits which commence at or before such age, or disability benefits paid to a disability retiree who is not eligible for or receiving primary social security disability benefits, or (ii) on the date on which such member first becomes eligible to receive primary social security disability benefits, with respect to disability benefits paid to a disability retiree who is eligible for primary social security disability benefits, or (iii) on the date such member separates from service, if later than age sixty-two. b. A member's primary social security retirement or disability benefit shall mean the social security benefit computed as of the time of separation from service on benefit levels then in effect. In no event shall a benefit payable under this article be reduced as a result of any increase in social security benefits which occurs after the day on which such member last separated from service. Provided, however, in determining the applicable date pursuant to the preceding sentence, any period of service immediately prior to such separation which was not allowable as credited service pursuant to section five hundred thirteen shall be disregarded. c. 1. A member's primary social security retirement or disability benefit, for offset purposes, shall be the member's federal social security primary insurance amount, calculated as hereinafter provided. In determining a member's primary insurance amount, only wages for service with a public employer shall be included during years of such service, and zero earnings shall be used for all other years in the member's federal social security benefit computation period. Provided, however, that a member's primary insurance amount shall in no event exceed the amount determined pursuant to paragraph two. 2. A member's primary insurance amount shall be determined under this paragraph if a lower amount would thereby result. In determining a member's primary insurance amount hereunder, only wages for service with a public employer shall be included during years of such service. The member's highest annual wage earned during any calendar year of the final five calendar years of service with a public employer shall be used for all years of the member's federal social security benefit computation period, if any, falling after such member's separation from such service up to age sixty-two if separation occurs before age sixty-two. Such highest annual wage shall be used for the final calendar year of service and, reduced by five percent per year for each year preceding such final calendar year of service, shall be used for all years of the applicable social security benefit computation period which precede the final calendar year of such member's service with a public employer. The primary insurance amount, as determined above, shall be then reduced by a fraction, the numerator of which shall be the total years and parts thereof (measured in months) of service with a public employer, and the denominator of which shall be the total number of years in the member's social security benefit computation period. d. The member's primary social security disability benefit, for offset purposes, shall equal the member's primary insurance amount. The member's primary social security retirement benefit, for offset purposes, shall equal the member's primary insurance amount

(i) reduced by five-ninths of one percent for each month, or part thereof, that separation from service upon retirement (or the date benefits commence, if later) precedes attainment of age sixty-five, provided that such reduction, in no event, shall exceed twenty percent, or

(ii) increased by one-twelfth of one percent for each month that separation from service upon retirement exceeds attainment of age sixty-five. e. Except as otherwise provided herein, a member's primary insurance amount shall be determined as provided in the federal social security act, and the rules and regulations promulgated thereunder. f. This section shall not apply to general members in the uniformed correction force of the New York city department of correction or to uniformed personnel in institutions under the jurisdiction of the department of corrections and community supervision and security hospital treatment assistants, as those terms are defined in subdivision i of section eighty-nine of this chapter, provided, however, that the provisions of this section shall apply to a New York city uniformed correction/sanitation revised plan member. g. This section shall not apply to a New York city enhanced plan member who receives the ordinary disability benefit provided for in subdivision c-1 of section five hundred six of this article or the accidental disability benefit provided for in paragraph three of subdivision c of section five hundred seven of this article.