Your sight sits above your line of aim (arrow path). This causes very close ranges to sight-in similar to longer ranges. The closer the target, the longer the range it will sight-in at. This will vary from person to person, because of different anchors. No one yardage will work for everyone. To sight your bow in like this would be a waste of time in my opinion. You might come close, but you would not be exact. For instance, if you were actually at 3.5 yards instead of 3 yards, it might make a difference of 5-6 yards downrange at the actually distance.

Your distances are backwards. The 4 yard distance should be the one to correlate more closely to the 30 yard pin.