I don't use NSFetchRequest so I can't comment on that specifically, but it appears to be something related to it. The code you use in your comparator block is just fine. I setup an array of the exact numbers you show and then sorted them using your code and everything worked out fine.
I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.