Jones is one of those backs that needs to get in a rythym. He needs a lot of carries. I think he will change his game in the offseason. He is trying very hard not to get injured, I believe. Remember everyone, he has yet to complete a season healthy, give him some time, this is new territory for him, he's gotta be worried some when he runs.
Barber, having never been injured badly while here, is still running like he is invicible. Which is what a back needs to do. Julius will get it back, don't worry.