my hold button is like being in 3rd gear the entire time, i dont think you could over-rev or stall with the button on

if im going over 30 driving normally, it will down shift to the 3rd gear, at 50 or so you should be in 4th or th overdrive, so it will down shift

but i have never been able to get proof of what the hold button is or does, but thats what im assuming