It depends on the machine. Some machines have the capability to make this adjustment based on run time, and others use crazy lasers and stuff to constantly make adjustments.
This is a significant difference in shank size, but I've suspected that this has been happening for some time now. Just that I don't own any large shank horns and I don't have enough free time to run to a shop and measure stuff. I really wish that manufacturers would get their stuff together on this, or at least be more transparent about it. A horn built for a larger shank size is probably not going to play too well with a smaller shank mouthpiece. I guess that's fine if you're trying to give players a bad impression of another brand of mouthpiece.
"Normal" (Bass Trombone) = 12.5mm
Some other size (Yamaha?) = 12.65mm (+3mm)
Mirafone Large Shank? = 12.7mm (+4mm) <-- I think Euphoniums have been using this recently
Chinesium example I own = 12.75mm (+5mm)