[Bigtop]

Originally Posted by mellody

[2008.01.01] SET LIST ~Greatest Songs 2006-2007~ (SET LIST ～グレイテストソングス 2006-2007～)

That's the first release and the original title, you can read the further information by clicking the link

So I think they just revised the album - they kept the songs there, and then they added it to reflect new favorites, and revised the title to reflect the changes... I think it might be a slight (not a full-blown) duplicate there...