Need For Speed :: San Andreas

Hi, i have Flash, and i had lvl 6 on heat lvl, i understand that it`s suppose to get decreased but mine it`s not going back up.
Someone said that i should take out more cops cars, and i got this here showing my problem:
https://www.youtube.com/watch?v=flf6Gk1r_ho&t=5s

What's your car score?
Availalbe heat level is limited by car score which has been increased recently and now C class cars can't reach heat level 6 anymore. That's why your level isn't growing.

My car score is 354.

So you can't get more than heat level 4 if I remember correctly.

And why this change?

Because WL6 is much more difficult with slower cars.