Plate Solve Settings

In the Plate solve settings window, under edit parameters…
What is the difference between “enable third order distortion”, and " highest accuracy plate solve"
Which is preferred for very large focal length scopes (F8 2438mm or F5 1536mm)

PlateSolve2 is from PlaneWave used with permission. Personally, I have tried changing the settings, but I didn’t see any performance difference for telescope pointing. Accuracy is more then sufficient.