As Kevmo says of Rossi’s test data ... it must be a typo.
(In reference to the 13,000+ kg H2 container that was weighed to an accuracy of about 1/4 gram on a bathroom scale that was calibrated by two people that knew their weight.)
They no longer use the membrane pressure gauges that were so popular in automotives decades back.
The chips backing them up are pretty good too. I find it amazing they've been able to attach intuitively obvious analog controls to them.
You could wire up a modern bathroom scale to weigh 1000th of a gram without a lot of effort. The question is no longer about the quality of the weighing device ~ more like the capability of the LCD or LED to report it.
It's not just that the future of technology is better and better stuff, some of it is better in ways no one can imagine ~ it's just there, and it's good.
We are changing our home lighting over to LEDs as we can afford it (which involves a lot of bargains BTW).