If it's a ProAm, I would bet my life that it doesn't roll absolutely perfect. You probably just haven't noticed the subtleties. I'm not knocking you, by any means... Most people don't notice the subtle drifts.
A ProAm has a plywood cabinet. It will move, throughout the seasons. I have a 9' ProAm, in my shop. It moves quite a bit, despite being in a controlled environment, on a concrete floor. The rolls may not be super noticeable, when playing. However, the levels don't lie. And, if you really take a close look, with a few slow-rolling balls, you'll see some drift.