'09 Es 350 Correct Tire Pressure?

[suxel 1]

Owner's manual and driver's door sticker both spec tire as P215-55-R17 and 30psi. A tire care nut, I had a mental note of the 30psi since the day we picked up the car.

However, checked cold tire pressures yesterday and they ranged from 32 to 35 psi. Then rechecked the tire size since we'd bought a new set from Lexus recently, but they were P215-55-R17. And noticed something illegible had been added in black marker to the door sticker.

Confused, I called our service manage and explained the above. Long explanation but what it boiled down to was the correct pressure for this region (Michigan) is 36-38psi.

That sounds a bit strange to me but I inflated them all to 37 and we'll see what happens. To me an additional 6-8 psi seems like a lot for the same car, same weight, same tire size as originally specd?

Anyone experience anything similar?