The number that has been talked about concerning the sales of this album has always been around 1 million copies.
What, then, is this?
http://www.avex.co.jp/e_site/tansin/0305_ni.pdf
Ayumi Hamasaki "A BALLADS" units sold 1,710,000.
edit,
I noticed this is the total amount of copies that avex shipped out to their stores. It's still impressive, all those 1.7mil copies counts towards avexs profit, not only the 1,1 million sold copies if I'm not wrong.
The article also mentions that RAINBOW shipped over 2 million copies, while the sales of the album is slightly under 2mil, according to wikipedia.