Oh, I didn't know there was already a case like this. I agree adding a new entry is the best solution so I've done that and I'll move over the albums released since the change. I'm not sure exactly when it occurred though, from our entries the closest I can get is between
Anime Digimon Xros Wars MUSIC CODE (Sep 29, 2010) and
THE IDOLM@STER MASTER ARTIST 2 -FIRST SEASON- 01 Haruka Amami (Nov 03, 2010). I've used Oct, 2010 for both labels for now.