OK, so if I understand it correctly, the bit resides inside the bushing, at least part way. In other words, part of the cutting head could be inside the bushing for shallower cuts. So basically, a bushing would be used with a straight bit to follow a template while cutting a certain depth. It wouldn’t be used with a bit that is wider than the bushing to control the depth of cut…so it’s basically like a flush trim bit in reverse.
Where are the band-aids?---Pro Libertate!