Not exactly. His numbers are forward-looking and are based on win expectancy, not wins.
Meaning, if a team gets completely outplayed but wins because of two 99-yard fumble returns, they don't get any credit for it because it's not predictive of future success. It just means a game that should have been a 41-14 loss was a 28-27 win because of two plays, both of which have a lot of luck involved (where the fumble happens on the field, who recovers it, how many yards are gained after the recovery).
The Nebraska game had a 70% win expectancy for Nebraska and a 30% win expectancy for Illinois (link here). We won more or less because of the Calvin Hart fumble return for TD and Martinez missing the wide open receiver when it was 6-2 (making the game 9-2 instead of 13-2). Play that game again with the same statistics - turnovers even, rushing yards even, Nebraska with 70 more passing yards - and Nebraska wins 70% of the time. A team putting up 5.5 yards per play usually beats a team putting up 4.7 yards per play if the turnovers are even and the total plays are even. This was one of the 30 out of 100 times that Illinois would win.
So rankings like these are based on the things you can control (move the ball/stop the ball) and not the things that randomly happen from game to game.
Put very simply, we've gained 1,410 yards and given up 1,926 yards and that's probably somewhere around the 93rd best team in the country.