An answer from Panerai tehchnical department:
"The perpetual calendar movement used in the FER15 and FER16 is built on a Valjoux 7750 caliber existing by Panerai on which is added an QP module from Agenhor .
This module exists already by Agenhor, but we have a specific version for Panerai where we added levers to ensure the position of the pushers at 30° to fit with our cases (usually this angle is much higher and moreover it is not the same for the pushers at 2 o'clock and at 4 o'clock).
Moreover, a lot of improvements driven by Panerai have been made on this module during its development."
Not that it matters, just a little clarification from a technical point of view..