I'm lost with your explanation of why the legend rings high with ferrous materials. The pie charts don't mean anything to me, so don't take it wrong if I sound like I'm not getting what you're laying down. You are an extremely knowledgeable detector with more experience and probably more education than me.
I dropped a peace dollar coin on the ground and it rang up high, the chunk of rusted iron rings up the same. Please someone explain in plain man words why the Legend (or any other machine) can be fooled between a 90%+ silver coin and a rusted bolt.
If no can answer this question, I may have left a lot of silver in the ground.
Mark in Michigan