[greenacres2]

A guess, and only a guess...is that the 1/2" guide bushing originally included in the kit had a short snout. Can't speak for others, but the guide bushings included with the Porter Cable jig are about half the depth of all of my other guide bushings--probably not much over a 1/4" deep, or just under the thickness of the template so that they never interfere with the stock.

 

[greenacres2]

A picture...

...can be worth a thousand words. Normal 3/4" and 5/8" brass bushings next to the same diameters from the PC dovetail kit. Note the difference in height.

edit...if that box top looks as good finished as it does in that picture, my daughter-in-law will love it!! I was really disappointed while sanding this afternoon, but there's hope!!