I think you're on the right track.
Back in the old days of Showroom Stock racing in FWD cars, modifications to the cars to make them handle were severely restricted by the rules, and some teams were known to run the rear tire pressures as high as 70 psi. We thought that was awful high, but never had any problems with those tires. Later we found out that some other teams ran their rear pressures at 90 psi.
