Wasn't overlapped. Not sure why you think it was. The edge guide runs along on top of the tape, and not on the base. The fact that it is raised off the base by the thickness of the tape changes the angle that the guide hits the edge. Small as that might be, removing the tape later then changes the angle again, and not in a favorable way.
i think you are looking at this wrong. If you are doing your side edge, the fact the base is thicker with the tape, shouldn't change the angle of the side edge angle. If it did, each and every side edge guide would have to be the exact same thickness and they are not.
are you talking about when you use the base edge?