You can select "Rating Math" and see the data and the computation so I'm still not sure where any outside influence comes in. Perhaps the teams are given different initial ratings so the "Opp Rating" is available early in the year? My only beef with it is that it seems to favor playing a weak schedule and beating teams by 10 as opposed to losing to some stronger teams. In my experience it's been surprisingly reliable - haven't seen many games where either teams rankings seemed wildly wrong. | 
