(1) Eligibility.[9] The following members are eligible for optional early retirement benefits:

(a) Any member of Plan J, Plan L, or Plan Y who is age fifty-two (52) or older and had become a vested member as defined in Section 22-105(47).

(b) Any member of Plan B or Plan D who is age forty (40) or older and had become a vested member as defined in Section 22-105(47).

(c) Any member of Plan A or Plan X who is age forty (40) or older and had become a vested member as defined in Section 22-105(47).

(d) Any member of either Plan A or Plan B who has twenty-five (25) or more years of credited service, regardless of age.

(e) Any member of Plan Y who has thirty-three (33) or more years of credited service, regardless of age.

(2) Effective date. Optional early retirement benefits may go into effect any time between the end of active City service and the month in which the member reaches minimum retirement age.

(3) Calculation of amount of benefits. The yearly amount of optional early retirement benefits is the amount of the regular yearly service retirement benefit (calculated in accordance with § 22-301) reduced by one-half of one percent (l/2%) of the service retirement benefit for each month the member is younger than the minimum retirement age. This reduction does not apply to members who retire under the provisions of § 22-303 (1)(d) and (e).