It's pretty detailed, so I can definitely understand it not making the fullest of sense. The fga/min thing is not normalized, yet I am pretty sure that copernicus is right. I hypothesize that this is due to the difficulty in getting high fta players close to their rl ftas, so they end up with about the same usage but the ratio of fgas is much higher, thus causing the shooting penalty...
...but it could be that wis just sucks at this aspect. Either way, if you're running up-tempo with a SL of 101.9, expect some games to have ridiculously bad fg% & high turnovers just because of outliers creating the penalty. You should end up between 7000 & 8000 fgas for the season, so if you're towards the lower end, you shouldn't hit too many bad cases. If you're towards the high end, though, you might have to plow through a dozen games or more with the penalty. Note that those dozen games aren't necessarily an L, though, as I guarantee you that you won't be alone.