You won't have any problems with this stool leaning forward to turn pages. The quote that you are misinterpreting from the maker is a warning about putting your weight down carefully after getting it off the stool, because it might could slip on slick surfaces when you sit back down at an angle. You're creating the idea of a 'stability issue' in your head, no offense.
If you're interested, I will gladly send you mine to try for a couple weeks if you cover the probably very modest shipping expense. I love this ding dang thing and really do think it's the droid you seek. I got mine on a lark for a super bargain used here off TB so I'm happy to pay the favor forward.