I have been detecting for about 7 years now and hunt 6 to 10 hrs. a week weather permitting and have used the ATP for about 60% of my detecting for the past 3 years so you could say I have the bug LOL. The most important thing I learned early into this was, when dealing with shallow targets is to listen and not look because the numbers have always jumped on all my machines when dealing with very shallow targets and a DD coil. Working the center of the coil and going to the toe or heal of the coil along with the fact I rarely have iron audio off and never use any discrimination so I can tell what my machines are telling me has helped a lot over the years. I basically cheated your test by going more off the sound than the numbers to be honest here. None of this means my ability's or technique is better than anyone else here so don't get me wrong when I say I listened a lot to old school detectorist's and not the metal detector itself when first learning how to do this. I cant speak for all brands as I have only owned the F-2, F-4, F-75 and ATP but on all of them, I used what is between the headphones for my discrimination 90% of the time. Bells and whistles are great when needed but learning the language is where it is at in my opinion. Not trying to knock what you are doing here but this is what works for me.