Lower tire pressure equals a larger tire footprint. I'm sure even you realize that as the tire is inflated it loses the bulge towards the bottom of the tire which indicates a decrease in the footprint of the tire. Although you may not notice it immediately they do wear out faster. You say that you haven't noticed the abnormal wear yet. But the question is how long have you run those tires at said psi? I do not want to cause an affront but 6 years experience slinging tires on multiple makes and models and hands on experience stands in stark relief as proof to the issues caused by over-inflation of tires. I will not disagree and say it does not aid in fuel mileage, it does, but in the long run it is bad. Mythbusters did a special on it as well and came with the same results that increasing tire pressures do help with fuel mileage but, they did also state that it was not worth it because of the decrease in the life of the tire. Also technically speaking, anything above 7 psi is excessive tire inflation. I hope this clarifies my earlier post.
