I have hit the gov a hundred plus times. Sometimes it gets to 118, other times 117. If there is a tiny grade incline, it’s usually 117. It should be governed by tire revolutions and not digital display MPH. There’s probably a margin of error with the velocity displayed that comes into play over 100 mph. Big soft tires make for more margin than cars with skinny rubber-band tires.
My first gov hits were all heading home on a slight incline, only hit 117 the first times. Never thought to complain about it.