This is simply to track the performance of teams who, whether home or on the road, are unranked-favorites facing ranked Dogs.
The theory is that the better team/ranked team should be favored over the worse/unranked team. Yet the ranked teams are dogs, so the "line" or the "books" are tipping their hand.
I know, I know this theory has not been back-tracked, and can be fit into the tinfoil hat section of betting concepts nevertheless its an idea worth tracking.