User blog comment:B214/Light Novel Volume 16 spoilers/@comment-9339850-20131018161752/@comment-1359322-20131018162314

Well it seems like Koneko receives some "upgrades" on her chest, so i don't think it's an illustration error, i guess Asia should start worrying now. She might not even be in 3rd place if Akeno somehow steals the 2nd place from her.