Some things to consider before turning up the temp...
a) How long was the machine idle before you took those readings? I ask because the group will get hotter as time goes by - not exponentially, but hotter nonetheless.
b) Does your coffee taste good? *If so, then this is a very good reason to leave it just the way it is.
c) What prompted you to take these readings? *If it was just for something to do, then resist the urge to fix something that aint broken.
d) The readings you have taken at the hex bolt will be different to the water temp as it hits the puck
92 degrees is far from the be all and end all. *I run a commercial 2 group at 89, because:
1) The coffees I use taste better to me at that setting, and
2) Ive tried different settings (higher and lower), different water flow rates, different coffees, different grind settings, under and overdosed, and it still tastes best at 89.
Hopefully that may put your mind at ease, unless of course, your coffee tastes sour.