I have a 24" digital Mitutoyo height gage (192-607) that is not measuring correctly. Everytime I raise it up and take it back to the zero point on the surface plate, it gains about 0.020". Also, if I raise it very far, after I have lowered it a short way, the display faults out to all 8's. The batteries were changed and that didn't seam to improve anything. Any ideas on what I can do to fix it?