if any exam besides 100 and 120 drop red scrolls, i've never seen it. I posted it as a bug but the mods think it's working as intended. I finished 120 a while ago but I feel bad for anyone trying to do 100 - 120, it very clearly does not work like every other sequence of ninja exams. Of course, haven't gotten the rare drop from 120 so who knows if that works either.