I am about to buy a new processor, and the MX-170 is high in my list of candidates. In the pictures of the unit, there are four AUX XLR outputs. Reading through the thread I believe these can assigned as additional LFE channels (I currently own two subs). Can they be assigned as additional speaker channels? I have one unused amp channel, how can I use the unused amp channel? Can it be assigned as a top center channel? Or as a third ATMOS channel?