Is there any difference between Sunnah, mustahabb and nafil?

Praise be to Allah.

The majority of scholars of Usool al-Fiqh say that there is no difference between Sunnah, mustahabb, tatawwu’ (voluntary actions) and nafil. But the Hanafis say something different. They regard mandoob (recommended) as being of the same status as nafil, and they differentiate between Sunnah and nafil, regarding Sunnah as being higher in status.