Assign Group to LR+M

Avantis is setup to use LR+M where LR is the mains left and right and M is the subs.
I have a stereo group for drums. This group is then assigned to LR and to M, but nothing is coming through on M.
What am I missing.
One thing that I notice is that where I assign the group to LR on the Routing - Groups page, there is a rotary control that shows the level, but where I assign the group to M, there isn’t a rotary control for level.
But if I use “Mix” button to change the send level from the group to M, it also changes for LR, which tells me it should work.

Any ideas?
Thanks

There is no “send” level from the group to L&R or M. This is on or off only.
The level you see is the level of the group master fader.

Thank you, so what you say is that I can send from the “drum” GROUP to LR and M as an on/off only, for both LR and M.

Thank you, so what you say is that I can send from the “drum” GROUP to LR and M as an on/off only, for both LR and M.

Correct. Your drum group fader would control the volume in the LR and M matrixes. However you can’t send more drum group to the LR than you do your M matrix the way this is set up - it will always be equal volume across the two matrixes based on the group fader position.