For crying out loud, I was about to write a whole reply trying to comprehend the madness behind it and then realized the date. Well played.
... I hope... [huh]
The author gives no details about his jig, other than saying a router can be used instead to cut the slots.
Given the angle fence on the jig, my guess is that he is also using the DF500 in a vertical manner like some people putting theirs in a third-party dock.
There may be some other explanations, and I'll try to contact the publish to see if I can find out more from the author. His article came out in February.