Sec. 4. SERVICE PENSION BENEFITS. (a) A member who terminates active service for any reason other than death is entitled to receive a service pension provided by this section if the member was:

(1) hired as a firefighter before the year 2017 effective date, including a member who was hired before the year 2017 effective date and who involuntarily separated from service but has been retroactively reinstated in accordance with an arbitration, civil service, or court ruling, at the age at which the member attains 20 years of service; and

(2) except as provided by Subdivision (1) of this subsection and subject to Subsection (b-2) of this section, hired or rehired as a firefighter on or after the year 2017 effective date, when the sum of the member's age in years and the member's years of participation in the fund equals at least 70.

(b) Except as otherwise provided by Subsection (d) of this section, the monthly service pension for a member described by:

(1) Subsection (a)(1) of this section is equal to the sum of:

(A) the member's accrued monthly service pension based on the member's years of participation before the year 2017 effective date, determined under the law in effect on the date immediately preceding the year 2017 effective date;

(B) 2.75 percent of the member's average monthly salary multiplied by the member's years of participation on or after the year 2017 effective date, for each year or partial year of participation of the member's first 20 years of participation; and

(C) two percent of the member's average monthly salary multiplied by the member's years of participation on or after the year 2017 effective date, for each year or partial year of participation on or after the year 2017 effective date that occurred after the 20 years of participation described by Paragraph (B) of this subdivision; and

(2) Subsection (a)(2) of this section is equal to the sum of:

(A) 2.25 percent of the member's average monthly salary multiplied by the member's years or partial years of participation for the member's first 20 years of participation; and

(B) two percent of the member's average monthly salary multiplied by the member's years or partial years of participation for all years of participation that occurred after the 20 years of participation described by Paragraph (A) of this subdivision.

(b-1) For purposes of Subsection (b) of this section, partial years shall be computed to the nearest one-twelfth of a year.

(b-2) A member's monthly service pension under Subsection (a)(2) of this section may not exceed 80 percent of the member's average monthly salary.

(c) A member who terminated active service before November 1, 1997, and who had completed at least 20 years of participation on the effective date of termination of service is entitled on retirement to receive a monthly service pension in the amount provided under the law in effect on the effective date of that retirement, unless a subsequent benefit increase is expressly made applicable to that member.

(d) The total monthly benefit payable to a retired or disabled member, other than a deferred retiree or active member who has elected the DROP under Section 5(b) of this article, or payable to an eligible survivor of a deceased member as provided by Section 7(a) or 7(b) of this article, shall be increased by the following amounts: by $100, beginning with the monthly payment made for July 1999; by $25, beginning with the monthly payment made for July, 2000; and by $25, beginning with the monthly payment made for July 2001. These additional benefits may not be increased under Section 11(c), (c-1), or (c-2) of this article.