GOG53Z0

IN MDI I CAN PUT GOG53X0Y0  AND IT GOES TO MACHINE REF. FOR THESE AXES . BUT GOG53ZO WILL NOT RETURN TO Z REF. POSITION. CHANGES EVERYTIME I DRY RUN A PROGRAM. BUT WHEN I HIT THE REF. BUTTON, IT WILL GO TO Z REF.  CONFUSSED, PLEASE HELP.

If G43 is active, G0G53Z0 , the dro shows toollength. If cancel tool G49, same position is Z0