A couple more points.
1. The height of the blade changes the length of the adjacent side of the triangle (Pythagorean triangle), therefore it changes the angle depending on blade height.
2. The size of the holes that mount the square bar with the angle marks will change the angle some. The holes have to be big enough in clearance to accept the cap screws that go through it to the bottom of the vise jaw. This slop in the hole will change the angle, so I make sure when screwing the angle marked bar into the vise, that I center the rod on the screw hole pattern before I tighten them.
There is really no way to make a guided system 100% perfect. On the WEPS you have a set of variables, and on other systems you have their set of variables. That is why we use the angle cube, turn the guide rods around to the non dimpled side, and measure each side individually. If you see some gross difference like, 3 degrees or something, I would send the unit back for a warranty issue, but Clay has a tolerance he puts his units through in QC before shipment, and I can’t see anyone rejecting a unit because of 1 degree of difference.I remember seeing a picture of Wicked Edge putting a Bar in the vise like a knife would be mounted and checking the angle marks for accuracy. During this process there is probably a limit where Clay would have the units rejected.