It seems to me that only small level 5 tournaments will let you do that and it is still the tournament directors decision at those. At futures, sweet 16s, supers, and endorsers you will not be allowed to. I think the rule is meant to keep high level players from doubling up on points. For endorsers it wouldn't make sense to endorse the same person for two age groups.
Ignore the trolls...
Lets go Klizan, Woz, and Roger!