Anyone care to explain what's the big diffirence between the 3 lvls of difficulty other then the extra 200-500 more ninja points ? i noticed that when i started doing survival trial with the normal difficulty i often got nice frags, but now that i can do the extreme difficulty most of the time i don't get a single frag and sometimes i get 1 useless frag, isn't it supposed to be more rewarding to do higher difficulty tasks in general ?