I think the reason with highly unequal JS/JR is that the G is programmed to shoot based on their JS stat, however JR impacts their shots but not their shot decision. So a high JS G will take very contested shots while his JR doesnt back him up. In the mean time, a G with a lower JS stat that is similiar to his JR will shoot easier shots because he is programmed to think he wont make harder shots and therefore his JR backs him up equivalently too. Just a theory.