It's not that intricate of a system tbh. It's basically a % variation in price and a 2 weekly sine cycle graph. Then just add an extra % for tuning parts and that's it. You are overcomplicating the game if you're willing to wait 2 weeks just to get an extra 50k sale price. 5 laps at Pan Am BMB will net you that much in 3 minutes.
I'd rather have the usual sell for 33% price if that means we have the system ready at launch. As it is, this feature is a little too late for me. I've already bought every car twice, every tuning part, every tyre, every paint/rims. I did get an extra 10 million today from selling dupes from the ticket bonanza a few months ago so it's not completely useless, but unless PD adds multiple new 20 million cars in the future it's just gonna be unused cash now.
I wouldn't sell a legend car, but some people just want to try a car, then move on to the next one. If you can sell the 917K for 18 mil for example, you can use it to buy the McLaren F1.
If you think I'm nitpicking, fine. But I've had enough of PD's cynical tactics and obtuse development process at this point. As someone who've been with the series since 1998, I just call things as they are.