The system is designed to grade a QB's effectiveness over the course of the season, rather than rate his performance for a single game. Thus, while a QB might complete 95% of his passes in one game, it is highly unlikely that one would complete that percentage over a season. (The season record is 70.55%.)
Same for interceptions. To attain the highest possible score on that component, a QB would have to have no interceptions for the season. (Not going to happen.)
The average yards/pass perfect score requires an average of 12.5 yards/completion. The NFL record is 11.17 and has stood since 1957.<P>