(a) The board of trustees shall assess each participant in a health benefit plan provided under the group benefits program who uses one or more tobacco products a tobacco user premium differential, to be paid in monthly installments. Except as provided by Subsection (b), the board of trustees shall determine the amount of the monthly installments of the premium differential.
(b) If the General Appropriations Act for a state fiscal biennium sets the amount of the monthly installments of the tobacco user premium differential for that biennium, the board of trustees shall assess the premium differential during that biennium in the amount prescribed by the General Appropriations Act.