(a) Any member having accumulated unused sick leave at date of retirement is entitled to service credit towards the service retirement annuity to which the member may be entitled. The credit for accumulated unused sick leave is one month for any period of fourteen to twenty-six days inclusive of the leave and one-half month for any period of five to thirteen days inclusive; except that, the credit for accumulated and unused sick leave is one year for any period consisting of 2,080 hours. Less than five days of unused sick leave may not be considered for the credit.
(b) Any member seeking to convert his accumulated sick leave to credited service, pursuant to subsection (a) of this section, shall pay to the system the combined rate of contribution for the employer and employee in effect at the time he seeks to have the accumulated sick leave converted to credited service. The member also shall pay to the system interest, as determined by the Board of Trustees, based on information submitted by the system's actuarial consultant.