I have Mach 3 and I reset my G54 offsets every day. When I shut the machine down the next day it's blank when I start up. I used the machine yesterday and as I read your post I went and checked it out and it was clean nothing retained. To many variables to say that your X0Y0Z0 will be in the same place when you shut down and start up again, and if you have stepper motors you have to zero every time as sometimes they want to creep. I only cut wood and I always leave plenty of stock.Maybe it's a good thing it does not retain the G54 you may get lazy and not check and scrap your next part. I downloaded all 154 pages of Mach3 I will read thru and see if there is anything on the subject. Art has a great product going with the the Mach 3, and has great service.
9lrac9 K2cnc owner.