I agree that 0.5 seconds aren't that much. And of course i know, that the difference between the cars can be quite track-dependent.0.5 second is OK. The difference in the real GTmasters is 3 seconds.
Don't compare only the drivers. There are always faster and slower drivers.If you look at the qualifying times, it was 3 seconds.
The fastest was 1.21.003 and the slowest 1.24.631