Tire psi in 100+ degree weather??

[Chamberpains]

I figure the tire manufacturers put a little effort into the capabilities of their rubber. So when they put the highest load rating at whatever cold PSI and print that on the side of the tire, it only stands that they then heated that cold pressure up to whatever conditions its going to be exposed to and see if it failed. If it failed it would be hard to market it in Arizona on a hot day.
I run whatever that max PSI is year round and I get 200,000+ out of steers and 350,000+ out of drives no problem.
My Michelin Steers are 120 cold psi and on hot running days I've checked them @ 135 psi hot. Then they cool down on break and the cycle repeats.