(a) The Board of Trustees shall reduce a member’s allowance if the member:
(1) received any accumulated contributions, other than additional contributions, in connection with a prior separation from employment;
(2) is credited with prior eligibility service; and
(3) does not repay, with interest to the date of retirement, the amount received.
(b) A reduction under subsection (a) of this section shall equal the actuarial equivalent of the amount, including interest, that is not repaid.