Yes, I know you said you renamed the files - all of mine have various names, but that's not a problem - the code comes out of the content of the files, not their names.
I'm a little confused to be honest if you can see 'rom-title', 'filename' and 'title' when you press Y, but you say the screen doesn't change between them.
On my copy of DraStic, the screen looks a bit like this in the right mode:
/media/appsSD/roms/DS/ ..
MARIOGAME 504a5b32
MARIOGAME2 4547f8d2
MARIOGAME3 50a8674b
X: return to main menu Y: switch display (rom-title)
Please ignore the colours in that example. I can't figure out how to turn them off on this board - it added them automatically.
In that example, if you want the code for MARIOGAME2 it'd be '4547f8d2'.
PS. Some of the rom titles can be a bit cryptic, so if it helps you can highlight the game in 'filename' mode, then without pressing any other buttons, press the Y gaming button twice the get to 'rom-title' mode and the highlighting will still be on the same game, even though the sort order will likely be different.