(a) Benefits provided under this chapter shall be offset:
(1) to the extent applicable, by any amount for incapacity received as provided by:
(A) Chapter 143 or 177A, Local Government Code; or
(B) any other statute in effect on June 19, 1975, that provides for the payment for incapacity to work because of injury on the job that is also covered by this chapter; and
(2) by any amount paid under Article III, Section 52e, of the Texas Constitution, as added in 1967.
(b) If benefits are offset, the employer may not withhold the offset portion of the employee's wages until the time that benefits under this chapter are received.
(c) If an employee's wages are offset, the employee and employer shall contribute to the pension fund on the amount of money by which the employee's wages were offset. An employee's pension benefit may not be reduced as a result of the employee's injuries or any compensation received under this chapter unless the reduction results from a pension revision passed by a majority vote of the affected members of a pension system.