At my makerspace, somehow the config file got messed up and we had to reset our PRS Alpha shopbot. When I zeroed the z-axis with the z-zero plate, it was about 1/4 inch off (plate thickness setting was correct). I ended up fixing the problem by going into setting Unit Values [UV] and changing the Z Resolution Multiple from 4 to 5. What is this? I also changed X and Y from 4 to 5, but I don't see a difference.