As far as using age-graded performances to determine place, bad idea. The same as using chip (net) times or some other formula. It takes away from the true essence of racing, the head to head competition. First across the finish line wins, first 10 across the finish line are the top 10, what's so hard to understand about this concept?
Age-graded performances can be fun to look at but they are also not an exact science. It's been shown repeatedly that they are biased in favor of those who are older for a variety of reasons, not the least of which being that they don't take into account the fact that the gradings for younger runners are based on times posted by professionals while the gradings for older runners are based on times posted by amateurs.