I initially thought Ferrocheck would help identify targets at depth, until I read the manual again, and it was designed to help identify shallower targets near the surface.
I guess it does help in letting you know that it is a shallow target for one, and also the amount of iron contained in the target. In a high trash environment with multiple targets and iron, the indication may become confusing though, but it is another tool to use in making your determination. Like most I still rely on the sound, and the Ferrocheck and VDI would come in second in making my decision to dig it or not.
I believe the next update with iron bias will also help in making your decision. If searching for targets, especially gold items, you will always dig some trash, especially aluminum, regardless of the detector, or you'll be missing out on some of the gold.
In making full long sweeps as stated in the manual, using Ferrocheck, you're bound to be going over numerous targets unless you are in some really clean ground, which is really hard to find nowadays.