Using Mix6to2 and phase

When using Mix6to2 how to you use the phase controls correctly when, say, for example;

Input = Stereo (2 separate mono channels)

So if 'expanding the left channel to both channels, and also expanding the right channel to both channels - would I use the phase control in this situation?

I get a fairly large change in sound when using the phase reverse control, but honestly it doesn’t sound too bad by itself.

Only if I wanted something to have reversed polarity. But then, I would not even use mix 6to2 for expanding 2 mono channels to left and right…

Just curious, what you use in that situation? Two separate sends?