According to stats at 86cm she is supposed to have the 3rd largest breasts of the iDOLM@STER girls but if you look at this piece of official art she looks as flat as a pancake especially when standing next to Miki and Takane whom are respectively ranked 4rth and 2nd in bust size at 84cm and 90cm.
Currently Reading: Bram Stoker's Dracula Currently Playing: Lego Star Wars: The Complete Saga (360), Rune Factory 2
Eh, it's just character art. Do you really believe that a 16 year old would have those kinds of measurements in the first place? Also, notice how Chihaya's supposed to have the smallest bust, yet in-game it's *really* hard to tell.