Doobie, I am not sure I understand the question. Discrimination and All Metal are two different modes. However, by turning up the disc. all the way, you are losing a lot of depth and you might not beable to pick up the silver dimes. Silver being the conductive metal it is will always read deeper than clad.
By using All Metal, the detector will pick up everything.
Good Luck Doobie,
Sandman