I had Lance 1161 and 1 of the first things I noticed in it was cold air coming from bathroom vanity. Turned that power cord compartment had open passage under vanity and shower, so I sealed it off at the time.
Other thing was heating duct into holding tanks compartment, who had no return.
Meaning the system is pumping hot air around the holding tanks and via gaps around the plumping - straight into the woods.
It wasn't till I parted the camper to notices like 2x2" openings around plumbing going via the floor, who never have been sealed. Not only air exchange, but open door for rats & mices.
So IMHO slight R difference in wall insulation is very secondary.