Sorry for delayed response, a situation prevented my availability; thanks Kent, your explanation kind of dovetails into the Old House Gardens note on same.
Old House Gardens considers Simplex to be a naming to modern Dutch forms of an old heirloom named Early Louisiana. Dutch growers have appended names like Sweeties, Cologne Bottle, and Simplex to their 'modern' renditions. The original daffodil, Early Louisiana bloomed much earlier than these newer simulations.
In my humble opinion, Old House Gardens is quite knowledgeable , especially concerning heirloom daffodils.