meowie, from my experience with yesasia they are selling jpn versions and they would make a distinction of jpn vs. not. also, if you look at:
http://www.yesasia.com/us/deji-deji-...0-en/info.html
you can see that the 'language' of the book is Japanese. maybe you can save that page and if you order and when you receive the item it is in Chinese for example, then you/we all have a legit argument against them subbing the wrong edition.
as for price differences, of course any seller can charge any price for any same item it wants, it is their loss/gain how competitive the pricing is. however i do know that for me in usa, the YEN starting about 4 months ago has become very expensive against the USD, hence sales to USA from JPN involve the Japan seller to have smaller profit margin, or raise prices. USA to HKD, no change since HK pegs its currency to the USD. But you may wish to look at your currency vs. HKD and YEN.