(a) Any person who became a member of the municipal employees’ retirement system after December 31, 1964, and who previously was a member of the state employees retirement system or the retirement system of any municipality not participating under the provisions of this part shall receive credit for the purposes of retirement under the provisions of this part for the period of service with the state or such municipality if the state or municipality voluntarily chooses to transfer to the Municipal Employees’ Retirement Fund from the retirement fund of the state or such municipality, by the authority having control thereof, on application of such employee, the entire amount paid into such state fund by the employee or the entire amount paid into such municipal fund by the employer and the employee as a result of the service of such employee, plus interest at the rate being paid by the retirement fund from which such amount is transferred from the date of each payment into such fund to the date such employee became a member of the municipal employees’ retirement system. No transfer of employee contributions or interest shall be required whenever a former member of the tier II plan in the state employees retirement system applies for such retirement credit. If a municipality not participating under the provisions of this part declines to transfer the entire amount paid into such municipal fund by the employer and the employee as a result of the service of such employee, the member may purchase all or a portion of the credit for the member’s prior service to such nonparticipating municipality by paying into the Municipal Employees’ Retirement Fund (1) two and one-quarter per cent or five per cent, as appropriate, of the member’s salary for the period of such service, and (2) the actuarial cost determined by the Retirement Commission as necessary to fund the increased benefits payable by reason of such purchase, together with interest at the rate of six and one-half per cent, compounded annually, on such payment. No credit shall be granted under this subsection for any period of service for which any governmental unit is or will be paying a retirement benefit or if such credit would result in multiple service credit for the same period of service. In the case of an employee who withdraws from the municipal employees’ retirement system and wishes to return to a municipality not participating under provisions of this part, there shall be transferred to the retirement fund of the municipality to which such employee is returning the entire amount paid into the Municipal Employees’ Retirement Fund by the employer and the employee, together with interest at the rate being paid by the Municipal Employees’ Retirement Fund as the result of the services of such employee.

(b) Any member of the municipal employees’ retirement system who was previously a member of tier I of the state employees retirement system and who, pursuant to § 5-166, withdrew all his contributions in the State Employees Retirement Fund upon leaving state employment shall be credited, for retirement purposes under this chapter, with such period of prior state service upon payment into the Municipal Employees’ Retirement Fund of an amount equal to the total of all contributions and interest refunded to him from the State Employees Retirement Fund plus five per cent interest on such refunded amount from the effective date of his withdrawal from the state fund to the date of his application for credit under this subsection. Any application for such credit shall be made to the Retirement Commission on or before January 1, 1992, or within one year after the applicant becomes a member of the municipal employees’ retirement system, whichever is later.