It’s not “mono” metering, it’s channel metering. Note that there is only channel input gain, not separate L and R pre-amp controls. One stereo pre-amp, thus one meter. If you solo a stereo channel, you should see the level for L/R channels on the Mains bus meters and could use the Pan feature to check the individual channels. If you need to have separate control over both channels of a stereo signal you would use the Link feature of two adjacent channels, Odd L/Even R.
Under what circumstances do you find the metered information insufficient?
