I used to check some Dole 400's, maybe 8 years ago. I remember them to be pretty accurate, as long as you had the right size sample. I didn't use the built in hanging scale cup to measure a sample size. I carried an external electronic scale to measure it. You also have to do the temperature correction for an accurate result. Seems like corn was the most variable, but corn has high variablility in any moisture meter due to the various kernel size. SRWW and soybeans pack into the cup better due to homogenuous seed. Also milo, but we don't like milo cause of the itchy dust!

I think for farm use at the dryer, the Dole is useful whereas a more expensive machine wouldn't like the environmental conditions.