This is by far not driven to perfection and this should also not show you the fastest line on iRacing. It's a comparison between the normal dry line and the wet line I would be driving in real life. 100% track state simulates it quite well, the less track state the more you can drive on the conventional line until the dry line is actually the fastest again. So don't take this as a coaching advice and do your own testing for each specific weather and track scenario!