...You actually can still connect all 11 speakers in "Normal" mode, but the active (hot) pre-outs will be dependent on the processing... so for example, if you are listening to a 5.1 track and activate DSX H+W, the height & wide pre-outs will be "hot" but the surr.back pre-outs will not. If you turn off DSX and turn on PLIIx, the back surrounds will become hot but the height/wides will not. If you then try to activate DSX (with the surr.backs live), it will toggle between DSX-W and DSX-H but not allow you to access DSX H+W because you are limited to 9 channels of processing.
And that, my friends, is why batpig's fame as a Denon expert is growing by the day! (see this post)