OK, I just got a Garmin 305. When I upload to Garmin Connect, I get one set of numbers. When I upload the same ride to the Garmin Training Software, I get different ones - particularly when it comes to total climbing. And it's not even close.

For instance, here are the totals for today's ride according to the GTC:
Elevation Gain: 4.107 ft
Elevation Loss: 3,679 ft

And Garmin Connect:
Elevation Gain: 2,444 ft
Elevation Loss: 2,132 ft

Other times, my average speed changes between the two, though it didn't this ride.

Am I doing something wrong?