Saved Track not as smooth as live display!

This is a long shot, but does anyone know how to fix this little anomaly on my GPS MAP 62s?

I record a track with 1 sec point intervals and the track displays beautifully on the screen as I'm walking it. (See photo # 1) However, if I save (or archive) the track and then look at it again on the screen, it is now a little "jaggy" and not smooth. This to the point where a smooth curve of 4 - 5 waypoints on the GPS device screen may become a straight line when I've just walked a 5m radius circle.

Any clues as to why, when after saving a track, the path I've just walked looks worse than when I'm walking it, live on screen? How to get that "live recorded" smooth track as a smooth file I can transfer from the 62s?

Many thanks in advance.

1. = display of current track on GPSmap 62s screen
2. = track saved and then displayed on GPSmap 62s screen
3. = current track saved as gpx and converted to .kml by "GPSvisualizer.com"
4. = .kml displayed on google earth