Texas Government Code - GOV'T § 845.110. Adopting Rates and Tables

(a) The board of trustees shall adopt rates and tables that the board considers necessary for the retirement system after considering the results of the actuary's investigation of the mortality and service experience of the system's members and annuitants.

(b) Based on recommendations of the actuary, the board of trustees shall adopt rates and tables necessary to determine the supplemental death benefits contribution rates for each subdivision participating in the supplemental death benefits fund.  The initial rates and tables become effective on the date that the fund and coverage become operative.

(c) On recommendation of the retirement system's actuary, the board of trustees by rule may adopt a mortality basis to be used in determining actuarial equivalents.  A mortality basis adopted under this subsection may not be applied in a manner that would reduce a participant's monthly benefit that has accrued before the later of the date the mortality basis is adopted or the date the mortality basis is implemented.