think this is due to the cars hdc file it is like a normal race07 file like this:changing from a session to the next, the tyres goes always to HARD tyres
FrontTireCompoundSetting=0
RearTireCompoundSetting=0
but a gtr2 car with different tyre choice it is written like:
FrontTireCompoundSetting=1
RearTireCompoundSetting=1