Mixes can be assigned to DCAs. But the DCA master doesn’t have any function on the asigned mixes masters. I don’t understand this.
If the DCA master is not going to have an effect on the mix master (which is an amplifier too that can be digitally controlled), then why add the mix to the DCA? Just to be able to mute it together with the DCA?
I find this at least confusing. What is this intended for? Just more mute groups? If so it should be clearer in the “DCA Group Assign” screen that adding a mix is not going to make its master amplifier digitally controlled but only muteable.
Better would be to make the mixes and LR master amplifiers also digitally controllable by the DCAs.
DCA’s are confusing at first. And yes, they are for raising and lowering a set of channels simultaneously. They won’t do anything at all if the faders that are assigned to them are all the way down. Try setting the DCA fader at unity gain. Then adjust the mix of the assigned faders. Finally, move the DCA fader up and down.
They are normally used as a master fader for all the drums or all the backing vocals or all the whatever.
Assign only LR to a DCA. Then change the DCA master value. Can you hear any effect on the LR bus? I can’t.
Sorry, I misread your post where you said Mixes. In my brain I was thinking inputs.
I don’t understand why anyone would assign L/R to a DCA but I’m no expert.
Don’t worry, it was my mistake anyway. There was no problem to be troubleshot or any missing feature to be derived from it. It was just me missing a PFL setting.
I’m sorry for the inconvenience and for the internet trash I produced… 
P.S. A possible use of a DCA containing mixes is to use its master as an overall volume master when you are using subs on auxes and want to keep their levels in ratio with LR. Then you would put LR and the needed sub mixes in a DCA, ajust their levels to each other, and then use the DCA master as an overall volume control. But I’m no expert either.
I like all my (wedge) monitors on one DCA. Then if I start to hear a little ring of feedback, I can easily tweek the levels down everywhere, before it starts blasting out.