Ahh, so now we get a better understanding of Dumble's actions and goals. I have to complement you on the second nastiest Manipulative!Dumbledore I've read, only the one in "Flames of Betrayal" is nastier. I love the fact that Harry hasn't been sitting back unquestioningly, but has been researching and thinking for himself; I wonder what sending a copy of this research to Hermione would do for her faith in Dumbledore after the revelations of Sirius' will?
You've still got some problems with verb tenses, but they didn't seem quite as noticeable in this chapter.