I just checked and when using external motion controllers, it is up to the controller to update the DROs, although I'm not sure how displaying different offsets is applied.
It's probably worth posting in the Galil forum, as you'll get more specific help there, as smurph (Steve) is one of the guys behind the Galil plugin and is more likely to see your post there.
I noticed you also posted on the yahoo group, so it's maybe also worth mentioning there that you're using a Galil, as it's more likely to be a Galil specific issue rather than a general Mach3 issue.