All truck scales usually weigh by 20 lb increments. I am a truck driver and any scale I've ever been to does it this way. My yard scale does the 20 lb dance every time. The scale operator times it to hit the lower weight. When I have time I am going to a certified scale and will weigh and compare. I was very suspicious for a while when I first got my new trailer, not knowing how much she'd hold. I simply walked on the scale, asked to see the readout counsel. I weigh 200 lbs on the dot ( most days). It read 200 lbs.



Now, whether they can manually tinker with it, or punch in whatever # they want when your sitting on the scale is another chapter.