You were getting mid tone for nickels. Atpro definitely is three tone. Run any PRO mode, notch in everything, run iron audio off, you will see Trackerman. You will hear the iron, no matter what the iron scrim number is set at. Avoid STD mode and keep Iron Audio Off, even for total newb beginners. Pro zero is zero, notch and iron scrim, dead zero, so it is quicker to set up if you like to hunt with little or no scrim.
The most important thing to remember is: as long as you are running Iron Audio off, it does not matter what you set the iron scrim number to, you will still pick up any iron as low tone, as long as it is not notched out by the REGULAR NOTCH SCRIM settings. REGULAR NOTCH SCRIM TRUMPS IRON SCRIM WITH IRON AUDIO OFF, ALWAYS. With iron audio OFF, you get true three tone, you will pick up all iron as low tone that is allowed (notched in) with the regular scrim. If the iron scrim number is set to max forty, but you have EVERYTHING notched in with the normal notch scrim, you will pick up the full range of iron, from one to forty, any and all iron, you will pick up anything you notch in, and it will sound off according to the id number, AS LONG AS IRON AUDIO IS OFF. Just because iron scrim is set to forty, you are not really scrimming out iron, if the notch scrim allows it. It gets more complicated. For instance, you could run zero notch scrim, max 40 iron scrim, and all iron will sound off low tone, no matter if Iron Audio is on or off, because Iron audio only allows targets to sound off mid tone that are above the iron scrim number, the max being forty before it breaks into mid tone. Iron Audio allows a normally iron response to come in as a mid tone response, only if the signal is at or greater than the iron scrim number setting. If there is a nail that registers 25 sitting next to a dime that registers 80, the combined reading may just bump up to 36, so it will sound mid tone if you have iron audio on and iron scrim set to 35. But with iron audio off, the two targets will sound iron, because everything below forty sounds like iron. Its madness.