(1) Upon retirement as provided in this act, the retirement system shall pay to the member or vested former member a straight life retirement allowance computed under subsection (2). If the member retires under the provisions of section 501(1)(d), the retirement system shall reduce the straight life retirement allowance as provided in section 501(1)(d).

    (2) The retirement system shall calculate the member’s or vested former member’s straight life retirement allowance pursuant to 1 of the following plan member classifications, as applicable:

    (a) For a plan 1 member, the retirement allowance is 30% of the member’s or vested former member’s final compensation plus 3-3/4% of the member’s or vested former member’s final compensation multiplied by the number of years and fraction of a year of credited service in excess of 8 years of credited service but not more than 16 years of credited service. A retirant shall not receive a retirement allowance under this subdivision that exceeds 60% of his or her final compensation. A plan 1 member who was holding his or her respective office on July 12, 1978, may elect to receive a retirement allowance under this section for an amount equal to or less than the computed benefit or to receive a retirement allowance computed under the state employees’ retirement system created by the state employees’ retirement act, Act No. 240 of the Public Acts of 1943, being section 38.1 to 38.48 of the Michigan Compiled Laws.

    (b) For a plan 2 member, a plan 3 member, or a plan 4 member who has less than 12 years of credited service, the retirement allowance is 3% of the member’s or vested former member’s final compensation multiplied by the member’s or vested former member’s years and fraction of a year of credited service. For a plan 2 member, a plan 3 member, or a plan 4 member who has 12 or more years of credited service, the retirement allowance is 50% of the member’s or vested former member’s final compensation plus 2.5% of the member’s or vested former member’s final compensation multiplied by the number of years and fraction of a year of credited service in excess of 12 years of credited service but not more than 16 years of credited service. A retirant shall not receive a retirement allowance under this subdivision that exceeds 60% of his or her final compensation.

    (c) For a plan 5 member, the retirement allowance is equal to the amount computed under subdivision (b) minus the amount of the straight life retirement allowance the member would have been entitled to receive or will receive from another publicly supported retirement plan as of August 31, 1981, based on the same judicial service accrued in the other publicly supported retirement plan as of August 31, 1981. The retirement system shall base the retirement allowance attributable to the same judicial service in another publicly supported retirement plan on service credit for service as a judge in that plan as a percent of total service credit in that plan.

    (d) For a plan 6 member, the retirement allowance is 3% of the member’s or vested former member’s final compensation multiplied by the number of years and fraction of a year of credited service. A retirant shall not receive a retirement allowance under this subdivision that exceeds $15,000.00 or 40% of his or her final compensation, whichever is greater. A retirant shall not receive a retirement allowance under this subdivision that when added to a retirement benefit payable under a county retirement plan exceeds 66-2/3% of his or her final compensation.

    (e) For a plan 7 member, the retirement allowance is equal to the amount computed under this subdivision. A retirant shall not receive a retirement allowance under this subdivision that exceeds 66-2/3% of his or her final compensation. The retirement allowance under this subdivision equals the sum of the following, as applicable:

    (i) 3.5% of the member’s or vested former member’s final compensation multiplied by the years and fraction of a year of service credited before January 1, 1983 for which the member or vested former member makes the 5% payment to the retirement system as provided in section 16(1)(d) of former Act No. 165 of the Public Acts of 1954, if any.

    (ii) 3% of the member’s or vested former member’s final compensation multiplied by the years and fraction of a year of service credited before January 1, 1983 for which the 5% payment described in subdivision (i) is not made, but not to exceed 40% of the member’s or vested former member’s final compensation.

    (iii) 3.5% of the member’s or vested former member’s final compensation multiplied by the years and fraction of a year of service credited after December 31, 1982.

    (3) The retirement system shall pay a straight life retirement allowance to a retirant for his or her lifetime. Except as otherwise provided in section 508, the retirement system shall not make an additional retirement allowance payment upon the death of a retirant receiving a straight life retirement allowance other than the full month‘s retirement allowance payable for the month in which the retirant dies.

    (4) At the time of retirement, a member or vested former member may elect to be paid an optional retirement allowance under an optional form of payment provided in section 506 in lieu of the straight life retirement allowance under this section.