Now that's an interesting bit of research, and his reasoning does seem sound about the continual halving.
I also loved the interactions between Draco and Ginny, I wonder if/when Harry will realize just how Draco feels.
Author's response
Harry's very intelligent, but he can't tell a crush if it bit him on the arse. Things will stay mellow, and Harry will be pursued for a while before he realizes it. Different reaction to the realization will be up on HPFandom.com when I post that chapter.