Huh, I guess it confused me because we haven't had a dress like this before in the catalog, it's only been minute differences in color. I should have just searched youtube:
http://www.youtube.com/watch?v=CayrvpZX230
Looks like characters got paired to share the same version of the outfit, like Ami & Yayoi, but it's different all around the pairings.
hmm
Not really, compare Iori.
In that video clip hers is pure red.
In the PSP images, it has a pattern
At 0:18 you can see Yukiho's arm, and it has no pattern. Yet the PSP images show a pattern.
Cause of the quality its hard to say, but there appears to be no pattern on Makoto's neck, yet the PSP images show a pattern.
So I believe the outfits are being changed to 1 per character.
Edit:
Taking a wild guess here, but:
Old = they keep the xbox 360 outfit
New = they get a new outfit
Ritsuko - old
Azusa - old
Haruka - old
Chihaya - old
Ami/Mami - old
Yayoi - new
Yukiho - new
Iori - new
Makoto - new
Miki - new
Takane - new
Hibiki - new