I don't know what tournament you were at and doesn't matter really. We had the same situation except my son is definitely not an A wrestler and was put in the A instead of B. He too only got to wrestle twice because of so many scratches in his bracket for some reason. He actually did pretty well, but part of that was because of a couple of those kids that didn't show (guessing sick). I think a lot of times it is the parents/team put the wrestler in an "easier" bracket, but from I noticed with the tourney we went to yesterday it was the host team that bracketed wrong.
Same thing if both brackets could have been combined as I am sure they could have if they were made aware first thing that kids couldn't make it after signing up he could have had more matches.