i have to admit i haven’t used page turn much, but i can’t say i noticed too much streching of the image. are you seeing this in a broadcast monitor or your computer screen? i’m wondering if you’re seeing a nonsqr image issue as the image is turned… usually with a page turn a verticle edge is turned towards horizontal axis.
if you’re using a d1 or dv comp setting then your pixels are a 10% taller than they are wide, so as the image’s edge gets turned the pixels will look streched about 10% when you see them on a computer monitor (which can only show your square representations of your nonsquare pixels).
a broadcast monitor would show you a more accurate representation of what is happenning.