Coordinate Accuracy?

I have a translation that converts from Garmin GDB which has Lat and Lon in WGS84 and converts it to UTM83-15F.  I noticed, however, that when I compare the position of my waypoints in my GIS software to those in Google Earth (Garmin Mapsource s/w has the ability to view the waypoints in Google Earth), they were off anywhere between 20 and 45 feet!.  The waypoints in Google Earth matched the data from the Garmin GPS unit to 5 digits, but the FME translation did not.  For my purposes this is too much error.

 

 

I then tested my GIS software which has an import system for AutoCAD DXF and Garmin Mapsource also has a way to save the GDB file into and AutoCAD DXF.  This is a round about and manual way to get the waypoints into my GIS software, but they are much more accurate, between 2.5 and 5 feet.

 

 

Can anyone guess as to why the large error is ocurring in FME?  I do use a reprojector to get the waypoints to UTM83-15F and I suspect that is where the error is ocurring.  Anyway to improve the accuracy of this conversion?