I don't think is so difficult to understand.
Chris, detailed the way to use registrations as "One Registration BANK for a song" (and he detailed this way, I don't write about it)
I, (and other users not only me) use Registration Bank to store 10 different songs (song=melody NOT songs meaning as files - wav, mp3).
My registration banks have generic names (as "Dance 1", "Dance 2", "Ethnic", etc). I select one of them and I press assignable button A (I set it to open Regist Info screen). In this page I see now 10 songs:
Regist 1: My song 1
Regist 2: My Song 2
.
.
Regist 10 : My Song 10
For each style I set all OTSs with different voices I want to use on that style. OTSs are like Registration Memory little brothers
The only difference is OTSs are stored in style file.
In this way, I can use Playlist function to create playlists and for 10 different records in playlist I will load the same registration bank file, but I will tick different registrations to be active on Auto Load function.
I don't use midi files, so this approach does not harmful my work, but if you use midi files I don't recommend to use this approach, because you cannot use OTSs for changing voices. OTSs will trigger Synchro Start button automatically, which is not good when you play a midi file. So you have to use registration memory to save different voices combination, which mean you will have to use One registration bank for one song.
Regards,
Vali