Well, here I am again with some BKool analyzing (Me on vacation in poor weather stuck at home is a dangerous thing :-).
I've been trying to figure out what could cause the abnormalities, which seems to happend quite often. My theory was that the system was vulnerable to (unintentional) "Time doping", because it was based on pc time in stead of pc ticks (pc ticks are number of ms since system was startet). I made a few test and voila! I was able to make a ride with both higher total speed and watts than the average speed and watt, just by setting the clock just before ending the session.
Many pc's are configured to update time via a time server, and every time that happens during a session, there's a great risk of screwing up the session.
There are other abnormalities to investigate, e.g. how J.MONTESINOS could be almost a minute behind Pep in "Percorso Monguzzo - Lurago d'Erba" in such a short event, even though he put out more watts. I'm out of vacation though, so I'll leave that to BKool