While most manufacturers provide an estimate of how much POI change can be expected for a given change in comb height (my Beretta nominally will change POI by 3 inches at 40 yards for each 1/16 inch washer inserted or removed), actual POI shifts may be very different for different individuals. My experience will not likely be the same as yours, or somebody elses. You do have to check it for yourself, whatever gun you are using. Further, it depends on where you break your targets. Typical is 30-35 yards, but your break point might be closer or further. The best way to set POI for the 16 yard line is to lock the trap for straight aways, shoot from station 3, and watch your breaks carefully. If the largest piece(s) fly upwards, you are hitting low. If they are flying downward, then you are hitting high. Adjust your comb upward (or downward) one washer at a time until your hits are centered with good, even breaks. It really is not important whether that point is a POI of 70/30, or 80/20, or something else. It matters only that, for you, using the sight picture, swing, etc that you shoot, you have centered the target for your style. Once this process is done, you are good to go with that particular gun.
Jim R