Match ups will always be gamed, so forget trying to address the total vs avg issue. Consider locking up teams for a longer period of time if you want to stop jumping and for teams that want to load up with a bunch of lv 1 players (ie: have them play a raid boss with their fellow lv 1 players). Ok, that was a rant. A real suggestion is that you should only face another team once. And depending on your bracket, you should try to force teams to have to play everyone in your bracket. So if you are top 10, everyone should need to play each other at least one time, and one time only. If people want to game the declaring by sharing info, then make their match up times even longer.