Well, that certainly blows Yellow Cake's analysis out of the water. Maybe it's not linear. It could be 700 minutes from atrocious to pitiful and then go up from there.
Interestingly enough my mini experiment documenting one of my players minutes played between mediocre and average experience was completed tonight. Here are my results:
im sure i read a bb post on that bb answers questions day where a bb clearly states that depending on the situation in a game exp gained may be different.