This is ranked by the most difficult schedules left, not the most difficult played or most difficult combined. If you order them in order of the cumulative percentage, then you would get the ranked strength of schedule. Looks like OSU should be top 10 and well above USC if that is where you are going. OSU would finish with a ranking of .5798... and USC would finish with a .5086...
If USC and OSU finish the season with one loss, there's going to be an uproar by whichever side does not get to go to New Orleans. We all want that shot at the Big Game. This is the problem that everyone has been waiting for the BCS to get into, and so far it's kept it's nose clean. Let's first worry about winning our remaining games, and then we'll worry about where we're going and over who/under who.