Does iPad rotate right sooner than it rotates left (or up or down)? If I don't have screen rotation lock turned on on my iPad 2 (OS 5.1) and am trying to use it in portrait mode, it's constantly rotating to the right when I don't want it to. Since it felt overly sensitive, I did a test to see how far it would have to tilt off of flat to rotate to a given direction.

To change rotation to up, down, or left, I needed to tilt it maybe 40 degrees off of flat. To change to right rotation, though, it only took a tilt of maybe 20 degrees.

I have the 'Clinometer' app (a fancy level), and its readings seem more or less accurate, so it doesn't seem like a problem with the accelerometer. Do others experience the same thing? Is there any setting I can change to tweak this?
I've just tried with an iPad (3rd gen) running 5.1, there doesn't seem to be a difference when I tilted left or right. At least, not a 20° difference.

But there could be. Since starting from iPad 2 there's the Smart Cover, people are more likely to tilt the iPad to the right, to have it in "typing mode" so Apple could have lowered the angle necessary to rotate the screen.