Ask HN: Weird ranking ...

As I write this, this item: http://news.ycombinator.com/item?id=2213180 is three hours old and has four points. This item: http://news.ycombinator.com/item?id=2213723 is only 19 minutes old, and also has 4 points. By my understanding, item ranking goes as points divided by a time exponential. By my reckoning, the second item should therefore rank higher than the first. Same points, but newer. And yet it isn't. The first item is ranked 63rd, the second is ranked 69th. I know that linkless submissions (like this one) get "punished" with a lower ranking, but what's going on with these two? Help?