This is what I am having trouble communicating. It isn't a plus or minus two game prediction, the vector of the uncertainty doesn't matter. It is simply that 80% of the teams will finish within 2 games of their predictions. It only matters, at least in my view, if you are trying to pick how an individual team will do, then you do have a four game window. Using other factors, such as coach effect, can give you a stronger indication of which way the vector for an individual team's over or under performance will go.
Looking at it broadly, even if you insist on viewing it as a four game predictive window, when in reality it is only a 2 game window (doesn't matter which side of the prediction you are on), looking at the numbers like this helps pin point coaches who are under or over-performing.
Under performing: Muschamp, Dooley, Kiff, Fulmer (later years), Saban (a bit misleading due to his talent, as he can never over-perform, although I can't find that he did when he had rosters that weren't the best).
Over performing: Spurrier, Jones (except last year), Petrino (at Arkansas), Franklin, Pinkel (except for last year) and Mullins.
About right: Miles, Freeze, Malzahn, Richt (although CMR is trending a bit negative of late), Stoops, Sumlin.