TRM VORTAC near Palm Springs gives a minimum DME of 4.9 taxying past it. Flying overhead at 30,300 feet is exactly 5 nm up and it gives a DME of about 9.8 miles.
The TEVUK waypoint on the Palm Springs approach gives 12.2 DME instead of the published TRM distance of 10.9 miles. Taking a right angle triangle of long sides 12.2 and 10.9 gives a calculated short side of 5.5. The cockpit displays give rounded distances and the sim might not have been exactly overhead TEVUK.
The Cochran regional airport where it is located is about 115 feet below sea level.
It is the same in mobile.