(a) Contributions allocated and appropriated under this subchapter for a state fiscal year shall be:
(1) paid in equal monthly installments;
(2) based on the estimated amount certified by the trustee to the comptroller for that year; and
(3) subject to any express limitations specified in the Act making the appropriation.
(b) A variation between the certified amount and the actual amount due for the state fiscal year shall be reconciled at the end of the fiscal year, and the annual contributions to the fund shall be adjusted accordingly.