It's kind of hard to confirm an elimination unless we have a witness at the mat. Usually we just notice that a team wasn't seen after a particular leg, so they must have been eliminated then. Or that say, team A and team B were seen on leg 5, we have no witnesses for leg 6 and 7 and all the other teams were seen on leg 8. Therefore team A and team B must have been the two teams eliminated on legs 6 and 7 but we don't know which team on each leg.
This season we don't have it all worked out yet, but we may figure out more now that the filming is over.