Discussion: So ?

Does this mean that Movescount is using GPS altitude correction and more precise DEM ?

No. It means pod's gps readings in xml file are not entirely useless, those are actually better than the DEM values AP uses around here. The problem is AP doesn't use those values, it either drops them or replaces them by DEM values, depending your settings. Unless you repalce GPSAltitude tags with Altitude in xml before you import them.

I also played with a climb calclualtion algorithm. I get decent climb readings If I use couple of seconds averages and ignore less than 5...6 meter bumps.

Do you mean that there is an improvement to older GPS chipsets ? I didn't paid attention to altitude data of GPS loggers lately.

Well, hat trick makes most of it. I believe your wintec may record quite good elevation readings when sued as a hat gps. Even if vertical accuracy gets 2 x worse than horizontal - if horizontal is about +-3 m most of the time, vertical is +-6m, that's good enough for climb calculation if you ignore smallest elevation changes and readings average a bit. DEM readings AP uses aren't perfect either.