It looks and sounds like the phase switch in the Control Room Mixer/ Setup-page has no effect on my system.
I can hear it click in and out, but without any audible or measurable (on my TC TM9) effect.
The volume-slider next to it, thought, works as expected…
Anyone who can confirm this?
Niek/ Amsterdam.
I think my opinion of a phase-switch is different from Steinbergs’:
I think/found out that the phase switch on the CRM’s Setup-page flips the phase of the entire signal, in order to get it in phase with other sources, and not just 1 channel from a stereo pair.
I found this because the phase switch in the Pre-section of a track seemed to have no effect on my system either, and that made me start thinking… 
Niek/Amsterdam