Macro command TRACK|MUTE basically doesn't work - what am I missing?

Two major issues with TRACK|MUTE:

1. It only works Globally on ALL tracks - not just the ONE selected track.

2. It only mutes tracks that have been previously (manually) muted/unmuted.

If no track has been previously muted, TRACK|MUTE does NOTHING.

I'm trying to create my own macro key that works exactly the same way as the built-in "M" shortcut key.

Can TRACK|MUTE mute only selected track(s) - not globally affect ALL previously muted tracks?

Can TRACK|MUTE initiate mutes on selected track(s) that have not been previously muted?

This is so simple, I'm kinda shocked that it doesn't work... maybe I'm missing something?

Thanks!