i have this option in the menyoo trainer, someone can explain me this please?

i opened with openIV a file called vehicle.meta in the Level folder and here i can set the value of dirtlevelmax and dirtlevelmin but i don't know how much value to put to make my car more dirty
i have this:
<dirtLevelMin value="0.000000" />
<dirtLevelMax value="0.850000" />

thank you, where i need to add this? on the vehicle.meta?

What is the value to add to this 2 levels for make the car more dirty and faster to get dirt, thank you