(a) The fee for serving a subpoena under this subchapter is the same as that paid a sheriff or constable for performing a similar service.
(b) A witness required to attend a hearing before the commissioner shall receive for each day’s attendance a fee and a travel and transportation allowance as authorized by law or a rule adopted by the finance commission.

(c) A fee under Subsection (b) is not payable until the witness appears at the hearing.
(d) A disbursement made in payment of a fee under this section shall be included in, and paid in the same manner that is provided for, other expenses incurred in the administration and enforcement of the statutes to which this subchapter applies.