The key thing in a scenario similar to what you post is that what is being decided happened DURING the match. So, if the coach wishes to have a conference about the ruling of a takedown at the end of the 3rd period, and that ruling would warrant additional wrestling, then by all means it is fair game for a conference and a potential change in ruling.
.
What we don't consider is trying to take an event which happens AFTER the match concluded, and then inserting it into the match results by trying to put a scoresheet notation inside of the match which could alter the match score (e.g., adding a penalty point) or alter the match result (e.g., declaring a 3rd injury time out after the final whistle which would then result in a loss by Disqualification).