Yep. Agree completely on both counts. The most I've seen my SurfGF at the aquarium was low single digits. I don't use the computer to keep me safe as these dives are all gas limited. I mainly use it to see how my SAC/RMV changes with different dives.
Had my worst ever RMV there last weekend. Dive was only 22 minutes, and my RMV was 1.06. This was a special event dive where the divers were part of a show for the aquarium guests. So, I was wearing a shark costume (Strike 1), doing a Red Light / Green Light race (Strike 2), and using a bubble gun hooked up to the regulator (Strike 3). That bubble gun uses a lot of air.