(a) A judge of the criminal law magistrate court may be appointed as a family law master and continue as a judge of the criminal law magistrate court.
(b) A judge of the criminal law magistrate court may not be appointed as a family law master unless the judge agrees to the appointment.

(c) A judge of the criminal law magistrate court appointed to serve as a family law master is not entitled to receive additional compensation for serving as a family law master unless the commissioners court provides additional compensation.