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We absolutely MUST start recognizing the different dynamics of a machine operating up hill vs. down hill.   I am strongly convinced that wheel slip on a combine is a bigger issue than flow sensor accuracy.   And the same thing would need to be factored into productivity maps.    My Dad thought controllers were a waste of time, until we got our first NH3 monitor in the mid 80's, and he saw the difference in rate when going uphill vs. downhill.   And he would never apply NH3 w/o a controller after that.

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