BoA & TVXQ new singles release date exchanged

[ayumisrael]

I have a doubt..I was comparing the album Secret of Ayu with Yui's album.
But they say this:
Total Sales Reported (by avex trax): 804,000 (Japan)
Total Sales Reported (by Oricon): 666,363 (Japan)
Why such a difference?

Avex's might be shipped copies which they get paid for (I think) but I don't think we should use any of avex sales I think we should only use oricon (for any artist, for any release) xD.