make sure the sensor plate isn't wore,or worn off.there are three different plates options and yours might have soft one.if you are experiencing hybrid to hybrid variations, this normal.  not talked about much though.we have a pf 3000 in our 2366 that is calibrated to the nth degree.we ran into a dekalb hybrid yesterday that the yield monitor was showing it to be 15-20% lower than the adjoining hybrid,checks via scale on auger wagon showed it to be 5% better.be very careful when making hybrid choices using yield monitor data.