This would automatically adjust the fader of a selected channel so the peak level matches the reference channel.
It would operate much like the EQ comparison. Open the Channel Editor for the reference channel, from a drop down menu, choose the channel you would like to balance with the reference channel. Cubase analyses the two and makes the necessary adjustment to the channel fader of the selected channel.
This would be good for when you change a virtual instrument but want the mix to stay roughly the same.
Then it shouldnt match to peak level but should match to RMS level.