(a) A local or regional board of education may establish a retirement incentive plan for teachers in its employ who are members of the teachers’ retirement system. The plan shall provide for purchase of additional credited service by a board of education and a member of the system who chooses to participate in the plan, of additional credited service for such member and for payment by the board of education of not less than fifty per cent of the entire cost of such additional credited service and payment by the member of the remaining percentage of such total cost. The member shall pay the remaining percentage of such total cost, if any, in one lump sum not later than thirty days after receipt of notification by the Teachers’ Retirement Board of the amount owed. Any such plan shall specify a maximum number of years, not exceeding five years, of additional credited service which may be purchased under the plan. Any such plan shall have a two-month application period.

(b) Any such member who has attained age fifty and (1) who would become eligible to receive a retirement benefit under subsection (a), (b) or (c) of § 10-183f if such member received additional credited service pursuant to subsection (e) of this section, or (2) who is not retired and is eligible to receive a retirement benefit under subsection (a), (b) or (c) of § 10-183f shall be eligible to apply. Any member who applies shall agree in writing, as part of such application, to submit a complete formal application for retirement to the Teachers’ Retirement Board on a date which shall be established by the board of education which employs the member, provided such date shall be on or before the last day of the school year in which additional credited service is purchased for such member pursuant to this section.

(c) All such eligible members may participate in the plan except that a local or regional board of education may limit the number of such members for whom it purchases such additional credited service in any calendar year to a specified percentage of such members in its employ on the first day of January of such year. If participation is limited, members with a greater length of service with the board of education, if they choose to participate, shall have additional credited service purchased before members with a lesser length of service with the board of education.

(d) The amount of additional credited service purchased for any member pursuant to such retirement incentive plan shall be uniformly determined but shall not exceed the lesser of the following: (1) Five years of additional credited service, or (2) an amount of service credit equal to one-fifth of the member’s total credited service, including additional credited service purchased by the member pursuant to the provisions of § 10-183e.

(e) For each year of additional credited service purchased pursuant to this section, the local or regional board of education and the member shall pay, in accordance with subsection (a) of this section, an amount specified by the Teachers’ Retirement Board equal to the actuarial present value, determined according to actuarial tables adopted by the Teachers’ Retirement Board, of the difference between the retirement benefit which the member is entitled to receive based upon the member’s service apart from such purchased service and the benefit which the member is entitled to receive including such service. The local or regional board of education may pay such board’s percentage of the entire cost of the additional credited service purchased pursuant to subsection (a) of this section in equal annual installment payments, including interest, not exceeding three times the number of years being purchased. Payments shall be made in accordance with subsection (b) of § 10-183n and rules adopted by the Teachers’ Retirement Board. Any late payments or outstanding obligations from a prior year’s purchase or from late payment of monthly mandatory deductions shall be included as part of the cost of purchasing such service. Any additional credited service purchased for any such member shall be in addition to any credited service purchased pursuant to § 10-183e.