Does a low ferrous number usually mean a good target?On the machine how high do ferrous numbers go and how high do the conductive numbers go?I was looking at a chart and it seems most ferrous number dont seem to go past 12 or 13 on buckles.I know chart is not perfect do to ground reading and other problems corrosion ect .But if you are getting high ferrous numbers is it usually junk?i know a lot of people dont hunt by numbers but i try to go through the screens like iron digital smart screen to learn the machine and what it is doing.Thanks for the help.