(a) A county or municipality may supplement, from its own funds, the salary of a department employee whose duties include providing services as part of, or relating to, the provision of child protective services and adult protective services by the department.
(b) A department employee who has worked in the same position for the department in a different region is not eligible for a salary supplement under Subsection (a) for a minimum of six months after assuming the position in the new region.

(c) § 659.020, Government Code, does not apply to the supplement authorized by this section.
(d) The department may not require a salary supplement as a condition for creating or maintaining a position in the region.