Part of what's driving me a little nuts about the 4psi rule is that it doesn't seem to account for environmental variables. What's the ambient temperature when measuring pressure cold? How hot is it on the pavement an hour later when you test it hot?
Maybe it doesn't make much of a difference, but I don't know.
What I was hoping for from Cooper was a table that mapped recommended tire pressure for a given weight on that wheel, targeting optimal tire wear characteristics. From what I can tell, none of the tire manufacturers are doing that, unless that is what their tables are trying to say (and not "this is the maximum load that can be carried safely at this pressure").
Off topic: I've used Cooper LT tires on a few different vehicles now, 3 sets in a row, and I've always been pleased with their performance offroad and their wear onroad. One person in this thread or another seemed to be saying they're not as good as BFG, but my experience has been that they're just as good if not better overall in performance, sidewall strength, etc. and probably better in terms of wear. I've also used BFG tires and Yokohamas as part of sponsorships previously, but when I'm buying I've been using Coopers. The Michelin XM-47 is also amazing, but probably wouldn't fit the LR4 without some modifications. ;-)