Will to Power and Superhuman

The attribution, by both Nietzsche and commentators, of Will to Power to an individual organism, is not merely arbitrary, but is inconsistent with the derivation of it.  It is arbitrary because he offers no grounds for ascribing volition to precisely and only that combination of cells.  But more problematic is that Will to Power is his replacement for Schopenhauer's Will to Live, which is a principle with respect to which the 'Individual' is an irreal Appearance.  Rigorously derived, therefore, Will to Power likewise transcends the 'individual' Human.  But, if so, then the Super-man that is the product of the Will to Power qua Self-Ovecoming can only be an origination of a surpassing of 'Man' qua species, not qua individual member of the Human species.  Most commentators follow Nietzsche in ignoring the former meaning of Superhuman and its implications.