(a) This chapter does not prohibit the commission from providing leasing services to a state agency otherwise excluded from its requirements.
(b) Services performed under Subsection (a) are not subject to the interagency cooperation law, Chapter 771.

(c) The commission may establish a system of charges and billings to assure the recovery of the cost of providing services under Subsection (a) and may submit, after the close of each month, a purchase voucher or journal voucher to an agency for which services were provided.