I just did an A/B comparison of the summed mono to channel one and my mic into channel two of the Bose,with both outs to channels one and two and,the mic through my Kn7000.

In my scenario, when I hooked up my second lineout to the Bose, the sound was a little louder,but not better and easily adjusted on my remote, and my vocal sound quality suffered by not using my intended preset.

My conclusion is that every case must be evaluated separately.If you have good mic alghorythms in your KB to compensate for not using the Bose preset,fine, assuming the sound is that much better using L/R outputs.

In my case,the mic output is less than stellar(as you know),and no advantage is there to be had.