(a) Each retirement annuity payable under this subtitle consists of a basic annuity and a supplemental annuity.
(b) A basic annuity is an amount payable from the subdivision accumulation fund and is actuarially determined from the sum of a member's:
(1) accumulated contributions; and
(2) current service credit.
(c) A supplemental annuity is an amount payable from the subdivision accumulation fund, subject to limitation under Section 844.008, and is actuarially determined from the sum of:
(1) a member's allocated prior service credit; and
(2) a member's multiple matching credit.
(d) Any increase in the annuity granted by a participating subdivision is payable from the subdivision accumulation fund as part of the supplemental annuity.
(e) A separate retirement annuity is payable with respect to each subdivision from which a person retires under this subtitle or is considered to have retired.