Yes, it is a very interesting experiment to try to conduct. Unfortunately, after trying the experiment a couple of times myself, as reflected in the thread, I'm only convinced that the RE92 wil reduce rolling resistance as high at 60 psi. Any farther improvements, or lack of improvements, are so small that they may well be hidden by the various noise sources. In life, we don't get to have a clear cut answer just because we want it
Hypermilers typically use 80 psi with this tire, but I've not seen evidence that they get improvement by going over 60 psi. I've begun using 60 psi on most of my Insights, and 44 on long trips for the comfort. I keep my experimental car at 80 psi.