College Sports: OU subject to fall in BCS standings

As an OU fan, I was shocked to hear that OU will fall to 3rd in the BCS poll if they don't beat Baylor by at least 40+ points and if Auburn beats Alabama by a heavy amount of points also. If OU has such an extended lead on Auburn, how is this possible? I know points matter. Also, OU is subject to fall because they didn't beat Nebraska by a lot of points. (I think that 27 points is a lot... 30-3) Just wondered why this is so and who does USC play this weekend?