They displays a differnt altitude data because they were made for different application and using different data-sources.
The ezTour plus was purposed to download and display the track logs only. It’s track information was real data on your trip way.
But the ezTour planner was purpose to create and edit the track line where you want to go. Then you could sync the track to our device. Its track information (altitude) was evaluated from height-database of the earth surface. Even you import other track format to planner, it always display the evaluation altitude form database only. This design could avoid our device display uncorrect track information when you used “Sync to Device” function on planner software.
Source: holux.com, translation reworked