(a) The executive director shall adopt a salary career ladder for parole officers. The salary career ladder must base a parole officer’s salary on the officer’s classification and years of service with the department.
(b) For purposes of the salary schedule, the department shall classify all parole officer positions as Parole Officer I, Parole Officer II, Parole Officer III, Parole Officer IV, or Parole Officer V.

(c) Under the salary career ladder adopted under Subsection (a), a parole officer to whom the schedule applies and who received an overall evaluation of at least satisfactory in the officer’s most recent annual evaluation is entitled to an annual salary increase, during each of the officer’s first 10 years of service in a designated parole officer classification as described by Subsection (b), equal to one-tenth of the difference between:
(1) the officer’s current annual salary; and
(2) the minimum annual salary of a parole officer in the next highest classification.