The updated Data List doc now has the missing info about the MIDI file format for the bulk dumps and parameter change info.
Funny you should say that - they just posted an updated Data List doc AND a zip file that has 14 Excel files in it for each of the main Data List tables.
https://usa.yamaha.com/files/download/other_assets/7/2172427/MONTAGE-M_DL_En_B0_web.pdf
They are now using 4 address bytes whereas before they were using 3 bytes.

Haven't done any comparisons to see if the two midi sections are the only changes made to the docs. So there could be changes elsewhere in the doc.