When assigning a function to a Fixed Channel button, the Main menu has two choices: 'On' and 'Solo'. In Allen and Heath terminology, these functions are called 'Mute' and 'PAFL'. Confusingly, 'On' means something else in Allen and Heath terminology, so I think that the button functions should be named the same as the host device. (Apologies if this is not regarded as a bug.)
Platform: iOS
Variant: Qu
This is an interesting question. As someone who uses MSP with a number of different mixers, I would like the labels to be as consistent as possible whichever mixer I'm operating. Q vs BW is another example. Perhaps an option?
MSP calls the Qu channel Send enables "On", which matches A&H's use. I don't have a Qu at hand right now, so I can't tell if that Main On selection is the bus enable or the channel mute.
MSP X-Air calls the channel mute Main On. That seems like it should be Mute. The LR send enable is called Assignment On, which matches A&H's use, too. MSP Qu doesn't have that function. It should.
Because MS-Pro serves a lot of mixers, I think also it will be a lot of work for David to change all function names to the mixer-function-names (doesn't it?). I work with A&H QU 16, but I think it is not soooo problematic to remember the MS-Pro-specific terminology, but I don't have Alzheimer yet ;-) (sorry, joke!). So most time I work with the MS-App... only for some specific things I do it on the mixer itself. Never had problems with the light terminology differences. But if it would be possible to assimily for MS-QU, I would not be angry... :-)
As already mentioned the goal is to have a unified UI for different mixers. Therefore the mixer specific terminology won't be applied everywhere.
The Qu version already has some specific labels for the buttons in the main mixer. I agree that this breaks the schema of the other views where the name "On" instead of "Mute" and "Solo" instead of "PAFL" is used.
So either I remove the specific labels in the mixer so the app itself is more consistent or I have to change all labels for Qu which makes the qu app consistent but not when compared to the other app versions.
The reason why the "Mute" button is called "Main -> On" in the custom button assignment is quite simple: The app internally stores the inverted state of the mute. Since the custom button directly accesses that data the button would be wrong if the data source is called "Mute".
But I also agree that it would be more explicit if the app would take care of that and just present the user a simple "Mute" source which is accordingly inverted.