I think you are on to something. I've always suspected that is the secret Ferrari Formula- for their road cars you simply divide the model number by 24 to see the real-world operable days in-between complete tear-downs. If it's the challenge version then simply convert the results to engine hours.
Applying that... with a 308/348 you get to drive 12.83 to 14.5 days a year, the 355 you get 14.7, and if you really want to stretch for the 360 or a 430 you see 15 to 17.91 respectively. Yes, it has certainly gotten better over the years like they say.
But... see, this is why I can't have an F50... it's like 2.08. :wink: