Sec. 19. (a) The pension portion (plus postretirement increases to the pension portion), provided by employer contributions, of the monthly benefit payable after June 30, 1989, to a member, or a survivor or beneficiary of a member, who retired or was disabled before July 2, 1987, shall be increased by three percent (3%).
(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.