In my opinion, this set is doing exceptionally well.
Think about it --- most of these songs have already appeared on the A BEST compilations, two of which were released just under two years ago. I fully expected the Japanese record-buying public to thumb their noses at it, considering it a "pointless" release. Not to mention, of course, the fact that it's a bit on the expensive side. There are obviously some mysterious market forces at work here, and I don't know whether it's the DVD, new songs/remastering, or packaging that was the deciding factor. (For me, it was the packaging and the fact that I never bought any of the A BEST albums, but I don't know if this applies to most buyers.)
At any rate, I'm happy for Ayu! I was a bit afraid that people were falling out of love with her, but that's clearly not the case.