I edit quite a bit of these anime enclosure entries, and most manufacturers just put the same disc in both BD & DVD enclosures. So I don't think it's necessary to create two entries since it's the exact same disc in most cases.
Aniplex do actually print ANZB and ANZX versions of the enclosure CDs (occassionally you'll find ANZB scans on vgmdb, i.e.
http://vgmdb.net/album/55154,
http://vgmdb.net/album/53210), but even they seem to be moving away from it now with more "ZX/ZB" marked discs.