What's up with Armored Core for Answer's sales?

[makingmusic476]

So I was looking at the Japanese numbers for the game, and noticed that the 360 versoin managed to sell 80k, only 20k less than the ps3 version.  I found that surprising, especially given the fact that the ps3 version had an opening week of 51k compared to just 24k for the 360 version.

So I compared both titles, and found quite a surprise:

http://www.vgchartz.com/swlaunch.php?reg1=Japan&game1=Armored+Core+for+Answer+-+PS3&reg2=All&game2=&reg3=Japan&game3=Armored+Core+for+Answer+-+X360&weeks=70

What caused the 360 version to suddenly shoot up around week 42 like that?  How does a game suddenly go from selling ~110 copies a week to selling over 2k?  And even now, it's still outpacing the ps3 version considerably.

Was there a bundle or something that I didn't know about?  Did the 360 version go platinum while the ps3 version did not?