I guess ive been lucky getting good scales, I use 2, both much older, a 505 RCBS and a Lyman m5, they have always been spot on accurate as long as they are level.
when Lyman went to plastic base scales things changed I guess, I had a couple bought on clearance but they are long gone.
got a little digital scale and its not accurate as the old ohaus beam scales. according to checks with those little aluminum tab check weights