86.1590.  Cost-of-living adjustments — base pension defined. — 1.  Provided that the retirement system shall remain actuarially sound, each of the following persons may receive each year, in addition to such person's base pension, a cost-of-living adjustment in an amount not to exceed three percent of such person's base pension during any one year:

  (1)  Every member who is retired and receiving a base pension from this retirement system; and

  (2)  Every surviving spouse who is receiving a base pension from this retirement system.

  2.  Upon the death of a member who has been retired and receiving a pension, and who dies after August 28, 2001, the surviving spouse of such member entitled to receive a base pension under section 86.1610 shall receive an immediate percentage cost-of-living adjustment to his or her base pension equal to the total percentage cost-of-living adjustments received during such member's lifetime under this section, but such adjustment shall not be deemed to change the base pension amount to which subsequent cost-of-living adjustments may be made.

  3.  For purposes of this section, the term "base pension" shall mean:

  (1)  For a member, the pension computed under the provisions of the law as of the date of retirement without regard to cost-of-living adjustments, as adjusted if applicable, for any optional elections made under sections 86.1540 and 86.1580, but in all events not including any supplemental benefit under section 86.1600;

  (2)  For a surviving spouse whose pension is prescribed by section 86.1610, the base pension calculated for such spouse in accordance with the provisions of section 86.1610, including any compensation as a consultant to which such surviving spouse is entitled under said section in lieu of a pension, but not including any supplemental benefit under section 86.1600;

  (3)  For a surviving spouse entitled to the continuation of an optional benefit elected under subsection 4 of section 86.1540, the base pension determined in accordance with subdivision (3) of subsection 4 of section 86.1540.

  4.  The cost-of-living adjustment shall be an increase or decrease computed on the base pension amount by the retirement board in an amount that the board, in its discretion, determines to be satisfactory, but in no event shall the adjustment be more than three percent or reduce the pension to an amount less than the base pension.  In determining and granting the cost-of-living adjustments, the retirement board shall adopt such rules and regulations as may be necessary to effectuate the purposes of this section, including provisions for the manner of computation of such adjustments and the effective dates thereof.  The retirement board shall provide for such adjustments to be determined once each year and granted on a date or dates to be chosen by the board, and may apply such adjustments in full to members who have retired during the year prior to such adjustments but who have not been retired for one full year and to the surviving spouse of a member who has died during the year prior to such adjustments.

  5.  The determination of whether the retirement system will remain actuarially sound shall be made at the time any cost-of-living adjustment is granted.  If at any time the retirement system ceases to be actuarially sound, pension payments shall continue as adjusted by increases theretofore granted.  A member of the retirement board shall have no personal liability for granting increases under this section if that retirement board member in good faith relied and acted upon advice of a qualified actuary that the retirement system would remain actuarially sound.