Texas Local Government Code - LOC GOV'T § 143.038. Temporary Duties in Higher Classification

(a) This section does not apply to a municipality with a population of 1.5 million or more.

(b) The department head may designate a person from the next lower classification to temporarily fill a position in a higher classification. The designated person is entitled to the base salary of the higher position plus the person's own longevity or seniority pay, educational incentive pay, and certification pay during the time the person performs the duties.

(c) The temporary performance of the duties of a higher position by a person who has not been promoted as prescribed by this chapter may not be construed as a promotion.