Don;John,
Excellent question you basically have to make up your own mind in the situation. Personally I go a tad higher if say I scrape the prop on take off, to allow the hot dogs a chance to break a fast time clock. Why should I hinder the race and a prestigious Fast time run.

Personally slower pilots should fly above the point leader, Now I'm not talking just a little slower. If you get Lapped in 3 Laps then why not fly higher to finish your race and allow the fast aircraft have a go at it. There trying for fast time and head to head comp. The slow aircraft creates a bottle neck and possibly a mid-air. Even in NASCAR the slower vehicle either comes to the bottom of the track or take the high side to allow the racers to race.

Mid-Air's immediate black flag! If possible pilots get off the course and waits for the finish.

Re-Fly's due to score/time keeper foul ups not the pilots. But now the re-fly causes a complete shift in points.