Settle down. I didn't attack your beam scale. In fact for 0.1gn the older scales are excellent. Unfortunately to get a new one of good quality recently is not really practical. Ohaus has reintroduced one of their models made in China but I don't know about the quality. Major issue is speed and wear over time. And yes some electronic scales are pieces of crap but many aren't. Regardless, they still need to re-zero because the digital display resolution hides zero drift. Unfortunate drift is a necessary evil of electronics. Your beam scale being an analog device makes it easy to see drift, at least to the resolution that the user can perceive in the line alignments. I bet you check for zero on every load.I have seen digital scales drift .2 grains. That is too much when trying to work up a load, and expecially when making max loads! My beam scale does not drift - period.
Now having said that, your beam scale will drift with changes in scale temperature. This is because the two balance weights are on different lengths of beam which grow differently when subjected to a different temperature. Small but there. You would probably need a change of 10-20 degrees to really see it. It's been many years since I routinely used one.