Tex. Gov't Code § 803.002

The purpose of this chapter is to implement the authority granted the legislature by Article XVI, Section 67, of the Texas Constitution to provide a program of proportionate benefits to qualified members of more than one retirement system to which this chapter applies. It is contrary to the purpose of this chapter for a person or class of persons to receive, because of service in more than one retirement system to which this chapter applies, proportionately greater benefits from a particular system than a person who has rendered faithful career service under that one system.