If I take my down range out of auto and select say 20', the unit always seems to default back to 80'. Is this normal? It seems like a pain because everytime I "stop sonar" to make a run then start it again it goes back to 80' and I have to go in and mannually change it back to 20'. It would be nice if it just remembered it was set to 20' before I hit "stop sonar". If I do the same but have the down range set to Auto it stays in Auto.