Anyway, without further delay, here's a quick plot:
The result? The times are tighter in the Mt Tam Double than they are either for the 2008 Dolphin Running Club Embarcadero 10 km running race or for the 2009 Mount Hamilton Low-Key Hillclimb.
A simple explanation is in both the hillclimb and in the running race speed is somewhat proportional to power. On the other hand, the double century includes time descending and riding on the flats, at times with considerable wind, in which a proportionate difference in power results in a considerably lesser difference in speed. So the result's not a surprise.
Of course the cut-off time has an effect, as well. You can really see that to the right of the plot. The "long tail" of relatively slower finishers is missing from the double results. Those who would have finished slower didn't finish, or didn't bother to start.
Anyway, it's a mistake to over-analyze the data. I thought the plot was interesting.