(a) Except as provided in Section 8.511 of this Charter and Section 8.511 of this Charter and Subsection (b) of this section, no person retired as a member under Section 8.584 for service or disability and entitled to receive a retirement allowance under the Retirement System shall be employed in any capacity by the City and County, nor shall such person receive any payment for services rendered to the City and County after retirement.
(b) (1) Service as an election officer or juror, or in the preparation for or giving testimony as an expert witness for or on behalf of the City and County before any court or legislative body shall not be affected by the provisions of Subsection (a) of this section.
(2) The provisions of Subsection (a) shall not prevent such retired person from serving on any board or commission of the City and County and receiving the compensation for such office, provided said compensation does not exceed $100 per month.
(3) If such retired person is elected or appointed to a position or office which subjects him to membership in the Retirement System under Section 8.584, he shall re-enter membership under Section 8.584 and his retirement allowance shall be cancelled immediately upon such re-entry. The provisions of Subsection (a) of this section shall not prevent such person from receiving the compensation for such position or office. The rate of contribution of such member shall be the same as that for other members under Section 8.584. Such member's individual account shall be credited with an amount which is the actuarial equivalent of his annuity at the time of his re-entry, but the amount thereof shall not exceed the amount of his accumulated contributions at the time of his retirement. Such member shall also receive credit for his service as it was at the time of his retirement.
(c) Notwithstanding any provision of this Charter to the contrary, should any person retired for service or disability engage in a gainful occupation prior to attaining the age of 60 years, the retirement board shall reduce that part of his monthly retirement allowance which is provided by contributions of the City and County to an amount which, when added to the amount of the compensation earnable, at the time he engages in the gainful occupation, by such person if he held the position which he held at the time of his retirement, or, if that position has been abolished, the compensation earnable by the member if he held the position from which he was retired immediately prior to its abolishment.