The posted coordinates are for the 1st stage of the multi cache.
At the posted coords you will find a lamp post. On the lamp post there are some letters and numbers. Type the number/letter combination when facing East (toward W. Lake Houston Pkwy) into Certitude checker below to gain final coordinates.
You can validate your puzzle solution with certitude.
Pevpxrg. Jngpu bhg sbe gubeaf.