If you pickpocket an NPC twice, then kill the NPC with the Blade of Woe - is the treasure off the corpse the same as what would have been the third pickpocket?
Also, does the increased percentage chance or # of pickpocket attempt have any bearing on the value of the prize? Because I got both the Breton Throne blueprint as a 3rd pickpocket attempt as well as the Coffin Lid blueprint as the 3rd attempt. That's not a very good statistical pool of examples, I know. I have received purple treasures off of the first pick pocket attempt.
I've been trying to get the Coffin blueprint off a vampire npc and the initial pct is 70%, then like 60 then 50, I can't remember exactly. (not counting if you wait a few seconds for it to jump up a bit, and success pct. number turns green). But I picked her twice, then left my computer for 10 minutes or so, came back and pick pocket pct was back up to 70%.