A member who is subject to the contributory pension benefit, the Alternate Contributory Pension Selection, or the Reformed Contributory Pension Benefit may purchase service credit as provided in subsection (b) of this section for periods of employment described in subsection (c) of this section for which the member is not otherwise entitled. A member who purchases service credit under this section shall: complete a claim for the service credit and file it with the Board of Trustees on a form that the Board of Trustees provides; and pay to the Board of Trustees in a single payment the member contributions the member would have made for the period of employment for which service credit is being purchased if the member had earned the prior service in the same part of the Employees’ Pension System or Teachers’ Pension System in which the member is currently enrolled, plus regular interest to the date of payment. A member may pay for service credit purchased under this section at any time before retirement. Subject to § 414(h)(2) of the Internal Revenue Code, an individual’s accumulated contributions in excess of the amount determined under paragraph (1) of this subsection shall be refunded on request. Except as provided in paragraph (2) of this subsection, a member may purchase service credit for a period of employment as a member of the Employees’ Pension System or Teachers’ Pension System if the member: has withdrawn the member’s accumulated contributions after a prior termination of membership; and was subject to the contributory pension benefit, the Alternate Contributory Pension Selection, or the Reformed Contributory Pension Benefit when the member previously terminated membership in the Employees’ Pension System or the Teachers’ Pension System. A member may not purchase eligibility service credit that exceeds the member’s creditable service credit.