[0.915 Balance Issue] I don't think +XP% Skills should affect Paragon.
Paragon says it increases the champion's level by 1. I think it would be better if it always just levelled the champion up once. It doesn't say in the description that it "increases the champion's level by 1 plus bonuses for all the +XP% skills". Besides, using the bonus Exp skills makes Paragon totally broken, if champions can get to ridiculous levels like 100.
So I suggest Paragon always levels up champions one level, no more, no less. Since the problem arises because XP is given rather than level increased, maybe a calculation could be done of how much total XP it would take to get to the very start of the next level and then "setting" the XP to that level, rather than adding XP to get to the next level, which is then affected by +XP% skills.
Anyway, the important thing is that levelling multiple times each Paragon cast is totally broken, so however it's done, there needs to be a way to always limit it to one level-up only each cast.