Ranking XP count from the time on, when you're added to the list the Keeper of Ranks makes.
I don't think this is really the case (luckily, because otherwise I'd have been stuck there forever).
For some reason or another, I was afraid to go into the black temple and even when I did, I didn't go straight to the keeper of the ranks. By the time I did, I already solved most quests and the first time I checked my rank I was already number two on the list (my star was rising rapidly I guess...).
