After spending way too much time on it, I think I have a satisfactory answer.

All the woodworking machinery manufactures say they have never heard of rating outlets by HP, as long as you are within the current rating you are fine. No one has ever experience a problem.

Leviton says the HP rating must be adhered to, whether the outlet is used as a disconnect or not; or a fire might result.
Hubbel says it depends on the controller; if the machine has a controller it should be fine. I said I had heard that maybe the HP rating is when the outlet is used as a disconnect. He agreed with that; if there was a switch it was okay. I have never heard of a switch being called a controller, but I guess that is okay.
Cooper said their outlets did not have HP ratings (despite the fact they do...). Since they don't have starter contracts HP rating wouldn't make sense. That seems to be saying they shouldn't be used as disconnects.

So my conclusion is that the two people I spoke to at Leviton didn't know what they were talking about; as long as you don't use the outlet as a disconnect, the HP rating does not apply.