Garmin 500 thoughts

I've been using the Garmin 500 with a Powertap Pro wheel for the past four days and so far I'm pleased. I just completed a 100 minute ride and the data on the screen is encouraging, but I'm suspicious that it's not recording zeroes into the average watts. When I'm coasting downhill, which is rare, the average watts stays put instead of decreasing. More later when I add a link to my workout.
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