This obvious hint; either intentionally misleading or correct information, but it indicates timezone somewhere near UTC. Well, it's weekend, so might also be more to east ;-)

Anyway, Europe, not US. If we can trust that.

These posting times could lead to something. He cannot post two posts at the same time (well,could, but most likely not). But Joe and the actual person are, for example, awake at the same time. Would need some statistics.