Jerry and Keith, you guys are on the bleeding edge (or alternately way too far down the rabbit hole!) on sub calibration.
If these questions belong in a different thread, I'll repost:
Are you doing gain-matching on identical subs or only mis-matched pairs?
Do you do this moving them to the center of the room thing just once unless you add/change subs or bass treatments?
My subs are all the same. I move the subs to the center of the room to conduct the gain-match, although there is evidence that this step provides little difference from careful mic placement with the subs in place. Since gain-matching removes the effects of the room, I don't think re-doing the gain-matching would be necessary when adding treatments.
I work out at a fitness center three times a week just so I can lift my subs, Keith. Although the furniture moving castors are sounding a lot better....