(a) If authorized by resolution of the commissioners or by council in counties having an optional form of government or by commissioners or council in counties having a home rule charter and approved by the retirement board, a special early retirement provision may be adopted for active members of the county employes' retirement system. The resolution shall state the terms and conditions of the early retirement and shall provide an election period which explicitly states the effective beginning and ending dates not be less than sixty days nor more than one hundred twenty days, with a seven-day revocation period after the active member's initial election. The election period must be followed immediately by the special early retirement period which is not to exceed twelve months.

(b) To be eligible for special early retirement, a member must meet the specified requirements established in the provision at the time of retirement during the special early retirement period. Minimum eligibility for special early retirement cannot be less than attainment of fifty-five years of age and ten years of credited service or thirty years of credited service with no age requirement. A member who is eligible for the special early retirement shall be credited with additional full years of service as stated in the resolution equal to no less than ten per cent nor more than thirty per cent of credited service, the result then rounded to the next full year, at the current designated county class base.

(c) The increase in actuarial accrued liability attributable to the special early retirement provision shall be determined by the actuary of the board and shall be amortized by level dollar amortization payments over the five-year period the end of which is the end of the fifth retirement system year occurring after the end of the early retirement period.

(d) No more than one special early retirement provision can be authorized within a five-year period.