Great info, Starmom. I have noticed very similar things with my own snakes.

Out of necessity through a lack of room (small apartment and annoyed BF), I had to cut down on use of tanks, which I prefer, and put my three largest BPs in a rack. HOWEVER I built it myself and used 90qt tubs which are @34"x15"x12". Of course, I would love to be able to keep them in the same RBI cages McKinsey uses, but those are way too expensive.
Before the rack was built, those three adult BPs (two females and a male) were being kept in much smaller QT tubs. The biggest girl, in her 41qt tub (only 6" tall) was miserable. She hardly moved around, and when she did it was to press against every spot on the lid. When I took her out she was always overjoyed.
The other two were in 26"x12"x10" tubs and were really cramped.

Once these three moved into the rack, the changes were quite noticeable. The girls relaxed and went back to normal BP behavior (hiding in the day and cruising at night) and started attacking their weekly rat with gusto! The male, who had a major attitude and hissed when anything came near him, is settling down and even showing himself more at night (before he hid all the time).

Any snakes in tubs in this house live in large, tall tubs. Plenty of cruising room.