@mogo103, First things first Welcome to VG Chartz!
Anyway it's kinda hard to compare Final Fantasy XII, a lot of people consider it to be one of the worst Final Fantasy games out. I liked the game but I did see a lot of flaws especially with the main characters and the story, I just liked the gameplay. Also some people didn't like the jump to the new style of fighting, FFXII is fairly differen't to the other FF's, which would explain the sales for it.
I'm just saying Final Fantasy has a way higher attach ratio for the first week, cmon now 1 in every 2 PS owners bought FFVII first week!, that's unheard of. But that's true that DQ is bigger in overall sales in Japan, but not by much.
We'll just have to wait for FFXIII to come out to see if Final Fantasy sales are going down, sales should be much higher then FFXII, like I predicted 1.6 - 1.9 million first week should be garunteed. It should be close to cracking 3 million LTD in Japan.