So why do I have to tell my customers that there tires are burnt out in the center when they treat there tires like a birthday balloon I caught on on my first 10 years heheThey are NOT over inflated! I've been doing this for over 40 years with excellent results in the ride, safety, wear, and longevity. The 90% rule just works!
The tire pressure listed in the door jam is a recommendation, not an absolute. It is a compromise to account for maximum load, maximum speed and other extreme conditions. And, if you change your tire size to something other than what came with the car, then that information is totally useless and wrong ... Think about it!
BTW, the maximum PSI listed on the tire is NOT the maximum that the tire can hold. It is however, the maximum that the tire manufacturer considers safe, especially under extreme conditions. The 90% rule keeps me in that margin of safety.
The bottom line is I'll stick with my 40 years of experience, but thanks for your concern.