From Aristotelis:
About BoP
(BoP depends on track)
"We follow official Blancpain BOP 2018 rules.
BOP A : Monza
BOP B: Paul Ricard, Spa, Barcelona (Spa might get an update after Paul Ricard race)
BOP C: Nurburgring, Silverstone
BOP D: Brands Hatch, Budapest, Misano, Zolder"
About setup in general
"Since AC1 we always try to have the actual setups of the real cars. Road cars had their actual road car values in AC. Race cars have real race setups on most occasions.
In ACC in particular they are based on their "base setup" of the manufacturer, taken from the actual technical manuals, or from race engineers setup sheets on each circuit. Whenever we can't have access on precise data, we will start from the base setup and try to get hints from the drivers and race engineers to create a "probable setup" for the car/track combination.
Certainly no "fantasy" with absurd numbers. What you see can be from "close to reality" to "spot on we use that".
EDIT: I could go as far to say that some setups for some real cars, have been tested on special dev versions of ACC and "worked" on the real track... but I won't say that because I can't bring proof, and also I'm not allowed to do so."