I think 5x10 is the best measure of performance on a day. Sometimes it really is a lot of luck to time the squalls correctly. The fastest run is a nice glory category but it doesnt separate a one-off lucky gust from the rest of the day. My 2sec/10sec PB was a very lucky gust- there was even a video camera on the beach to capture it

In ISWC competitions the "lucky gust" factor comes into it a lot for a result in a round, since they only count the best 2 runs for each round, but this becomes less of an issue once you get 5 or more rounds in. In Karpathos, its common for there to be only one or two solid gusts to come through in a round, and only a handful of people will be in the right place in the queue to nab it. That makes a huge difference to the results. I suggested to the pres that they should increase the number of runs averaged per round to 5.
My comment earlier on Benny's big day was that from the indications of speeds being done "at the same time" => similar conditions, Ben ~might~ have had some competition overall had Pete not had a plane to catch :)
Maybe a better way to measure performance is to discard the best 2 runs and cound the 3rd to 7th best times. That would kill off the lucky gust factor entirely.