I think this covers it. You won’t be able to adjust the voltage yourself. It will be relevant to the amps. For example, when you have the ground interference, the live voltage is way too low. So it pierces, but it’s reading at around 30v. THC tries to compensate by raising the torch, but it can’t go high enough to hit the target voltage so you get crappy cuts/ no cuts.
Voltage depends on torch height and arc length. Even telling firecontrol your target voltage is 120 won’t guarantee it hits it.
I reserve the right to be wrong, and will accept any correction given.