I just got my Prius last Sunday, and after reading posts here on better fuel economy, I decided I would try upping the pressure on the tires a bit. I wonder if some of the fuel economy could now be off. So we know that odometer readings are based on tire rotations. But if the tires are over inflated, could that throw off the circumferance of the tire, leading to less tire rotations covering the same distance. So, even though you cover say, the 50 miles, the car's computer / odometer thinks you did less miles (since less tire rotations are required). So could that give a false low MPG rating?