I encountered one of these when working on a conference. The system I had to set up was a stereo system with subs plus a set of stereo delays down the room. Owing to aesthetics the cabs had to be put where they looked best rather than sound best but I was able to delay the subs to the main stacks and set the delay speakers delay time as well. Using the 3rd input (C) I ran the subs on a separate aux send from the desk. I also used the dynamic eq to remove some frequencies during an evening disco, but leave them in during normal presentations to keep speech and playback sounding good.
I'm working with a different company soon and I'm going to recommend they get some of these units.