well you are right and wrong, on whole field the ag leader is pretty close,but on hybrid to hybrid differences the ag leader monitor is notoriously inaccurate, we weigh all crop harvested via weigh wagon scales verified by calibration loads to the coop.  we have a  weightronix scale foreman, so all loads and dumps are recorded.   just went through some field loads the other day, and the ag leader monitor in our 2366 was within 3% on whole field totals.   but hybrid to hybrid differences could be up to 20% in error,   dekalb has one hybrid that the ag leader monitor really can't get a good read on
  
 precision's setup is supposed to pickup on these hybrid to hybrid variations.