Sec. 26. (a) The pension portion (plus postretirement increases to the pension portion) provided by employer contributions of the monthly benefit payable after June 30, 1998, to a member of the public employees' retirement fund or the Indiana state teachers' retirement fund or a survivor or beneficiary of a member of the public employees' retirement fund or the Indiana state teachers' retirement fund who retired or was disabled:
(1) after July 1, 1983, and before July 2, 1995, shall be increased by two percent (2%);
(2) after July 1, 1975, and before July 2, 1983, shall be increased by three percent (3%); and
(3) before July 2, 1975, shall be increased by four percent (4%).
(b) The increases specified in this section:
(1) shall be based upon the date of the member's latest retirement or disability;
(2) do not apply to benefits payable in a lump sum; and
(3) are in addition to any other increase provided by law.