Hey guys!, I can explain that one, it's the safety ratings for insim I think, as only the MRT is available in Cargame OW most of the time, even if you have up to 90% safety rating. It shows all the Formula cars available though, and the percentages are as shown:
Class 14 1400 550 FO8 85%
Class 11 1100 200 FOX 75%
Class 10 1000 100 FBM 70%
Class 9 900 000 MRT 60%
Some special classes like FJR (FOB + 20% restrict / 70 kg mass) and FBX (FBM + 20% restrict) were also part of the cars that can be driven on there. As you mentioned Dave, it was about the same time 6H came out so maybe that's why.