Tom That gravel pit scale you are talking about.
There is a couple here locally that leaves their scale on. One pit only has one set of scales. The other quarry has 2 scales. When they are closed, evenings, holidays, weekends. Both places leave their scales on. The quarry leaves just 1 scale on. They both have a digital readout on the side of the scale house. The digital readout is in 20-pound increments. Meaning, if you weigh 19 pounds, it shows 0. If you weigh 21 pounds, it shows 40 pounds.
The place next to you just might leave their scales on 24-7. Will not have the "truck" traffic when they are closed. But you will not get an "exact" poundage. You get the exact weight when they are open, but have to pay for it.