Meta Blouse Sizing?

[tsulalaa.livejournal.com]

I was looking through Meta's Sweet Poker series and I was wondering about their sizing on these blouses.

http://www.metamorphose.gr.jp/category/select/cid/370/pid/9645
http://www.metamorphose.gr.jp/category/select/cid/370/pid/9646
I'm hoping linking to the site is okay. If not, I don't mind changing it.

Both of them have shirring on the back, but their measurements only have a single number, not a range.
Does anyone have any experience with Meta's blouse sizing? What's their normal range?
I looked at lolibrary for comparison to other Meta blouses, but it only lists the official measurements too. Is that number the max?