Mine seems to already doing what you described (unless I'm just lucky that they're appearing in that order) - the four threads showing up in subscribed threads are as follows in terms of "last post":
Today 4:02am
Yesterday 8:44pm
Oct 20, 2014 12:31am
Oct 15, 2014 4:15pm
What order are yours appearing in (if there is some sort of obvious order to them)?
By the way, I've alerted a mod to move this to the tech support forum.