From what I've read in another thread, that's incorrect. It seems as though it's based on strength of field according to this:
https://www.gtplanet.net/forum/threads/championship-points-scoring-system.367630/
Your DR affects the score, and yes the DR of others as well, but it's more than just your finishing position and the field make up. It also scores your drive.
You can have a terrible mistake filled drive and finish second and score fewer points than a perfect drive where you finish 3rd or 4th. It's happened to me and the competitors remain fairly consistent.
Even if I am wrong about it, and it's just coincidence that the scoring is different, we have all seen the old penalty system in action. You could apply half throttle in a full throttle area and scrub off penalty time. You could brake in a non braking zone and scrub off time. The game most definitely knows where you should be doing what.
Also, the AI knows what to do and where to do it. Obviously, the AI has to be using some indicator of where to brake and where to accelerate. If the AI can use is, the scoring system can as well.
I think PD have made a bold, but overly-risky and possibly naive move with this new system. It promotes cleaner driving, at the expense of more random frustrating incidents and more-disjointed races. However, it may be a wise move if they are confident that the small but mostly dedicated bunch of Sport Mode players will grow to appreciate this new direction. I would guess that 95% of people who will ever enthusiastically play Sport Mode are already doing so and will see the new system for its benefits. The potential problem is if new, inexperienced players are put off due to the harshness of penalising the slightest of imprecisions.
As the old saying goes, you only get one chance to make a first impression. The bulk of players already tried Sport a long time ago, made their judgement, and moved on to other things if they didn't like it.
This change now is indeed very risky because I am surely not the only player saying "no way" to Sport mode races for the time being.
With fewer players, matchmaking is more disjointed. With lesser drivers getting more lenient penalties, it will drive away higher rated drivers. If you survive corner one, and you are up front, things will be fine. I'll see what the middle of next week is like.