What happens with these new Coinmaster & Prizm units is, at least in my soil, the ID bounces around alot, but mostly in 2 adjacent IDs, & the IDs go lower when coins are deeper. So if everything below zinc is rejected, a 5" deep dime might be silent. Some of the more expensive White's locked onto 4" deep dimes, & on rare occasions, deeper. I got an ID lock on 4" deep dime on Ace 250. But what really impressed me was the Garrett AT Pro locking onto dime range & it really was a dime, and 7" deep in somewhat mineralized & very dry ground, in a park hunted 100s of times. Best wishes, George (MN)