Not sure if mentioned or intended but when you make a double post and it gets added to your old post, the time your post was made updates to the time your second post was posted.
So if I make this post at 11:55 and come back 3 minutes later and add a post (and no one else posted), the black bar above the post will read 11:58 instead of the 11:55 the first time I posted.
It's a little weird for a guy like me who double posts all the time.