Philosophy

Order Description
In On the Genealogy of Morality, Nietzsche argues that the notion of freedom of the will provides the slaves with a way to see their own weakness as virtue and to vilify the strength of the masters as morally reprehensible (GM I, 13). However, even though he attacks the notion here, just a bit later in the book (GM II, 2-3) he seems to reverse himself and praise as an ideal the so-called sovereign individual, in part because such an individual possesses a free will and great responsibility. What are the differences between these two conceptions of freedom of the will? How can Nietzsche consistently hold that latter one is to be affirmed and the former one rejected?
Please use On the Genealogy of Morality as a primary source, and use other secondary sources as well.