That chart is from the Hudy setup book ;-) But to be honest, it's already quite dated. It still has tremendous value (as does the whole book), but does not reflect how the latest touring cars are setup, e.g. ignoring flex settings and having stuff like gurney strip.
For me the order would be:
1. tires
2. springs
3. oil in shocks and diff
4. droop/rear toe in/flex
5. all the other settings
When the grip changes during the race my best bet would be either stiffer springs or stiffening the car with flex settings.