You've only shown half the procedure. Calibration of a measurement device is at both zero and span at a minimum. The span accuracy of the scale needs checked with `150 lbs of weight. There is usually a span adjustment in the base of the unit. If you can't adjust the span separately, it is better to at least calibrate using the procedure in the video above at 150 so that it's accurate near the range that it is actually measuring.
Hi John, sorry to say you can't do a span on this type of scales, you can only verify weight, they are mechanical using a spring and rod mechanism, once that spring stretches or the rod bends, they're no longer good,
