very well, to be fair, here is a shot at the limit at which distortion occurs. Moving in the vertical plane, I'd say the distortion occurs at about the same point on the other side as well.
As for being "not noticable", this effect is very obvious for a 180 degree viewing angle in any direction as Nanuq pointed out with his photo of the PO on its side. If you rest your hands with your watch face pointing up, this is noticeable to observers (admittedly only from a rather close range). It's also noticable to the wearer if you like to rest your hand in its side.
The point is not how noticable this effect is, suffice it to say that it bothers me and I'm looking for a fix to this problem short of buying a new watch. Thanks for the replies so far guys.