I also have no official knowledge on the matter.
That said, I would do it as:
1. Fill Beneficial Deeds
2. Randomly remove 12 of the remaining tiles.
3. Place tiles on the Map.
4. Place remainder in stacks.
This is since I would expect that the tiles for BD should definitely be there, unlike the stacks of leftover tiles which can be empty. Otherwise you 'could' get empty spaces on there which seems wrong.
I would agree this makes more sense.