Your FairPick scale may need to be recalibrated from time to time. This requires a 50 lb. calibrated weight. Note that a scale recalibration requires you to break the metal seal required by Weights & Measures. To re-certify the scale, you will need to contact your state Department of Agriculture.
Here is a link to PDF instructions on the recalibration process. You will need to remove the round cover next to the bottom scale display to access the system buttons.