This happened in two different matches with my son - on mat 5 - the last time in the last few seconds causing him to lose by one point. Another time he had his competitor pinned but it wasn't called and then in the next round he was called pinned in microseconds -video backs up that his shoulders weren't down -ever- but the ref. called it.
We,too, saw this same inconsistencies with other kids.
I think the tournament was great experience for him - the other wrestlers were tough and provided him with experience he can't really get in practice. I just wish the calls were consistent.
(Just a note - I understand that these refs. are human and their jobs are judgement calls. Frustration with sports calls is just part of the sport.)