I was just curious. I have been reading the manual on iron disc if there is iron nail that reads 20 and you increase it just above it like 25 so its not heard but if there is a coin under the nail. Lets say a quarter with the nail silent would it read up in the 80s or is it goin to be the conductivity of both targets and read lower. I have got about 3 or 4 hours on the pro i have been runnin the iron disc on 39 until i read the manual that i could be missin some targets.