I think you are right. IMO the weightage is around 2:1 in the favor of driving. So Inside Shot is important, but not nearly as much as Driving. Generally I think around 7 IS is good enough to hit 75%+ of your driving layups. (of course provided you have good driving relative to your opponent's OD/ID/SB) Also, I believe that when a player surpasses the defender and beats his OD and is at the ending stages of his layup and is facing a big man SB is taken into account much more than ID.
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