increment / decrement all marked values

[larsonscan]

You can mark and transpose the marked parts indeed through the nerd-menu.
SHIFT+DOWN in marked mode is already used to mark all
SHIFT + CURSOR LEFT/RIGHT/UP/DOWN is already used in the new version for another mark possibility

Leaves only the nerd menu for functionality. For now as you know, transposing a semitone and a octave are possible. These could be changed into a increase/decrease which would have the same effect for transposing but would include also other functions. Not sure if you only asked for transposing.

this seems kinda counter intuitive.. why not just have a second click of the mark button select all. rather than shift down? which would free up the shift UP/DOWN for incrementing/decrementing multiple values..

2nd mark = exit mark mode and copy into clip board

ah right. well there must be a better solution than having to go menu diving to change multiple values simultaneously..  nerdseq has 16 buttons!... 
a DMG only has 7.. and you can do it in lsdj.. if you select say some notes in a pattern and hold A.. you can transpose all of the selected notes up and down using the dpad..

Sorry but menu diving is a different thing. You don’t have to jump from one to another menu etc. This is on a top level and one button away.
I am not a friend of weird shortcuts and I am not planning to introduce them. They are very few exceptions and it must be worth the effort and added complexity.

I thought the idea was to mimic the functionality of lsdj in the first place. maybe i missed the point. in case you missed it. i posted a video to demonstrate this simple and extremely useful functionality that exists in LSDJ (even the old ass version I have running on my dmg)..  it also exists on the other two popular hardware trackers (i wont name them here).  https://www.youtube.com/shorts/6nPKqdHEYFE