DiRT Rally 2.0 suffers from the same issue, unfortunately. The "soft lock" option does not work in my case, and I am pretty sure that modern rally cars, such as the R5, do not feature 1080º on their wheels, otherwise the drivers would not be able to negotiate the turns correctly (most likely, it is around 540º in modern rally cars).
This is something that have frustrated me as well. It worked for me in DiRT Rally, but not in DiRT Rally 2.0. Also, after seeing some onboard clips from Norwegian rallying, I realized that quite a lot of the older cars that are being used aren't entirely at historical spec.
Then there is a whole discussion about DiRT Rally 2 and the historic cars, how historically accurate they are etc.
In my mind, the older cars in DiRT Rally 1 and 2 are not run as FIA Historic class spec. But more like what's allowed in e.g the national classes in Norway, so 540 degrees is inside what the "real drivers" use.
So, ye. 540 is what I use on my BMW. It's enough that I have to manually change button mappings between H-shifter cars and paddle-cars, so I don't bother changing the wheel range for every car I drive