Any help with bottle caps on the MXS? Depending on rust content of bottle cap, I get anywhere from zinc penny up to quarter readings for them. I have used other machines in the past that came with DD coils and those just had an inherent difficulty with bottle caps(hello Fisher DD) but wanted input from other users regarding the pesky bottle caps. I've also considered going with the 9.5" Sport concentric coil as that coil type on my old M6 was reliable with properly id'ing bottle caps. Anyone try that coil yet and can give feedback?