Jimmie, as mentioned by other above, and in the Denon manual, it is normal for the delay distance to be longer for the sub, because of the internal circuitry. I've left mine at the auto setup distance and it still rocks the house. Your mileage may vary.

I have the same experience. My Denon 3805 thinks the sub is 25ft away. It is actually 10ft away. But the EP600 works flawlessly, so I don't change the distance setting for the sub on the AVR.