Correct, and all eight channels can be set as subwoofer.
I use my unit for 2ch, where I have 2 channels set for the mains, and 2 channels set for the corresponding subs. The other 4 channels are not being used.
If and when a firmware upgrade is released being able to pair up channels either for multiple subs, or for a satellite and sub as in my setup would be excellent. Even being able to merge different channel graphs would be a great start IMO.