Confused over hitch weight

[pattonsr]

2009 Airstream specs for 27 fb classic from Airstream website

Hitch weight is 790 lbs
UBW is 6525 lbs
NCC 2475 lbs
GVWR is 8800 lbs

Question 1. I thought GVWR - UBW should be the NCC. 2275 is not 2475. Where did I go wrong? Or is the NCC incorrect?

Question 2. If I put the 27fb by itself on two scales, the hitch on one scale and the dual axle on another, what weights will I see? 790 on scale 1 and 6525 on scale 2 or 790 on scale 1 and 5735 (6525 - 790) on scale 2?

Thanks,
Barry