NRPN parameter mapping for Channel Mute QU-series

I’m looking for the definitive Parameter Number to address channel mutes on the Qu-series of boards via NRPN Midi messages.

I found documentation for the (newer) QU-5/6/7 series that looks like these should work:
B0 63 3D B0 62 00 B0 06 00 B0 26 00 (mute off/mic on)
B0 63 3D B0 62 00 B0 06 00 B0 26 01 (mute on/mic off)
(i.e. no particular parameter selection in the 2nd and 3rd CC triples, mute state value in last triplet)

But this doesn’t seem to be working for the older models with v1.9+ firmware.

It seems unlikely that that mute parameter has been left out of the otherwise consistent NRPN implementation, but the MIDI documentation refers only to Note On messages for channel mutes.

I am developing a ShowPlayer app that remote controls mute states on digital mixers and am looking to create a protocol template for A&H users. Note On is a possibility, but it requires Midi channel strip setup on the user side which could be avoided by finding the right parameter for Mute. Any solid info on this?