My theory is this-
JS, IS and PA affect shot selection. THe more IS the more inside shots attempted. The more PA the less bad shots taken. The more JS the more bad shots taken (since outside shots are usually bad shots in this GE ;))
From pure observation (no hard data) JR also alters shot selection. If a player has high JR, he will try for more long-range shots and since OD is universally overtrained, he will fail most of the time. If a player has low JR though, he will try for more midrange shots and be also more successful. If you play Motion with a PG that has low JR, but high JS and DR, he will mostly drive and shoot midrange shots. If you put a JR monster on same spot, he will mostly shoot from distance. It's also worth noting SG spot will almost always take more longrange shots than PG or SF.