I think each compound (RH/RM/RS) should have own PI rating. This is a problem in all lobbies with different tyre types (Sport vs Race etc.) and also renders RH tyres pretty much useless in 10 minute lobbies.
This problem is seemingly also acknowledged (and fixed) in Gran Turismo where you select maximum compound before the race and set power (PP) accordingly. In the race using for example RH tyres gives you more power but more grippy compounds are locked out - problem solved.
There’s already a Power/torque fine tuning suggestion which would solve how to set up correct power level for each compound.