Yeah, it was 50% in the originals, hopefully its about the same here.
Another question, how come theres this level cap thing? The original system worked fine, it was for pokes you got in a trade. If its your own pokes you overlevel for your stage in the game, good for you if thats your style.
If its because of the multi region campaign thing, then still, why is it there? You arent a different trainer, youre the same person, there isnt a reason you shouldnt be able to use your own pokes. If the reasoning is because it makes it too easy, well then so what? Players arent poops, if they make it a squishfest for themselves then surely thats their own problem? Likewise, if they choose to do the campaign with a new set of pokes, theyre free to do so. All youd have to do is stop them from using HMs.