Yes, the changes made to the Advanced Swing Mechanic put a premium on you executing the exact shot you are aimed for. So if you were someone that got by on doing like a -5/+5 kind of swing, you are going to become less accurate. There is no miss-hit if you nail the backswing length and follow through speed exactly right. But as you get away from those perfect points, more miss-hit is added. It isn't a random amount, it is quantified by how far off from perfect you are in each area. The only random to it is if that miss-hit is added to the left or the right.