What could i be missing F75SE???

Hey everyone, i'm using the F75se which is brilliant i tend to use these settings
Between 70 and 99 sensitivity( altering according to chatter)
Mode JE or BP depending on how i feel
2 tones
Disc 20
I live in the UK
During 40 hours of use i have found a 1793 manchester penny, numerous old silver coins, copper coins, silver buttons, a brass candle snuffer 1800's or older, and other interesting relics
so i am doing ok with my little time with this machine i love it.
My question is with these settings what could i be missing?
what settings do you use?
Any tips would be gratefully appreciated.
Thanks

The usual suggestion involves reading through these three threads:
[www.dankowskidetectors.com]

Thanks mate, i love this forum very helpful people. top man