How was the timestamp of the data again created. I know i read it somwhere but don't remember. Was it UTC timestamp is there a problem with daylight savings time of Japan? As far as i understand UTC is a constant "world time" and all timezones of the earth a derived from UTC.
Is something known, that there is some problem with the timestamps like Mark K. changed (for whatsoever reasons) , the timesettings of servers or something like this?
Have you found an inconsistency?
I'm pretty sure they should be consistent with UTC, I take the timestamps directly from that returned by each one of the APIs, and I don't think there are any problems. If you think there are though, tell me which ones and maybe I can have a quick look. If you're just speculating though, then you should be fine. UTC is pretty easy to get right, his servers should just automatically sync with a reliable timeserver in order to get reliable UTC.