Really? My elevation numbers have been pretty good... the garmin gives me strange results sometimes unless I click on the "compensation" button to account for actual survey data.
Also, you need to be a paying member (Friday power tip - there's a free trial code on the clyde club home page) to sort the results.
I didn't know it was the HRM giving the power results, I thought it was more to do with speed, altitude changes and other calculated stuff. They obviously can't account for wind, maybe that's where HR comes in. No clue.