I've got the same problem, and thought I came across the fix in this thread:
https://www.cnczone.com/forums/mach-software-artsoft-software-/210234-xhc-wireless-pendant.htmlSomeone from the XHC company seems to have posted the solution in theory, to load up a custom macro to one of the buttons that enables 'MPG Increase mode'. What I think we are looking for is for the MPG to operate in velocity mode - the faster the wheel is turned, the faster the axis moves. I'm not actually interested in absolute movement amounts. I can't get velocity mode to work at all no matter what I try. I can either move fixed increments (STEP mode) or a small distance at a fixed speed, in CONTINUOUS mode. If anyone has any suggestion I would love to hear it!