Mussolini started out as a hard-core Socialist (Thug/"Community Organizer" variety), he really had much more in the way of true Socialist cred than Hitler ever did.
At some point the idea that he personally was the smartest guy in Italy to turn it into his dream Socialist state popped into his egotistical little brain, and that's when he became a Fascist.
Hitler was actually his imitator in his early rise to power, and a lot of the unsound, cockeyed Fuehrerprinzip Nazi ideology comes from Hitler's interpretation of Mussolini's success setting up a goal for Hitler himself, not as something that sprang full-blown from German experience or his own warped imagination in isolation.