N.Y. RSS Law § 553

§ 553. Additional pension benefit for members of optional twenty year\nretirement plan. a. A participating employer which has elected, or\nwhich elects to provide the benefits of the optional twenty year\nretirement plan for its employees as specified in section five hundred\nfifty-two of this article may elect to make contributions for the\npurpose of providing an additional pension pursuant to this section for\nmembers in its employ who are entitled to a pension pursuant to section\nfive hundred fifty-two of this article. Every member employed by an\nemployer which participates in the retirement system and which has\nelected the provisions of section five hundred fifty-two of this article\nand this section may elect to be covered by the provisions of this\nsection by filing with the comptroller a duly executed and acknowledged\nform prepared by the comptroller for that purpose.\n b. Upon retirement, each such member shall receive, for each year of\nservice in excess of twenty, an additional pension which shall be equal\nto one-sixtieth of his or her final average salary; provided, however, a\nparticipating employer may elect to provide any service credit earned\nwith a public employer prior to services performed as a sheriff,\nundersheriff or deputy sheriff towards the one-sixtieth allowance and\nprovided further that the total allowance payable pursuant to this\nsection shall not exceed three-quarters of such member's final average\nsalary. The additional benefit provided by this subdivision shall be\navailable to a member after his or her employer elects to make this\nbenefit available to all its members otherwise eligible to receive this\nbenefit.\n