We have a straight edge bolted to the table that is aligned with the Y axis. We align everything against it and then set the x, y and z using the origin point on the plug, or in this case the jig. If the jig is not hard up against the straight edge everything will be out of alignment in a radial direction from the origin. In cases where the jig or plug is longer than the table we have to slide it along the straight edge and use an intermediate origin point. If the jig changes to an angle on the side there is less, or no, straight edge on the jig to align with the straight edge on the table and it sets us up for way more chance of a misalignment.