Dealer Tire Pressure

I received my new Toyota Prius in mid-March and immediately loved the vehicle. I was averaging 47 mpg right off the bat, with a few hundred miles well over 50 mpg when I took it up to the Platte River to see the Sandhill Crane migration. From my reading, I knew that I needed to get an accurate tire pressure gauge. I didn't get around to that purchase until last week. When I checked the tires, I found that they were very high: 47, 47.5, 48, 47.5 psi. These are the standard tires that say right on them that they should be inflated to no more than 44 psi. I tested the tire pressure after the car had sat overnight in a garage at 45-55 degrees F. At the point when I tested the pressure, there were around 900 miles on the car. I immediately dropped them down to 40-42 psi.

I feel so silly for not checking the pressure sooner, but I was under the false assumption that the dealer knew what they were doing. In all likelihood, did I cause any damage? Maybe some extra tire wear? Moral of the story: check the tire pressure the first day off the lot!!!