On the RCBS/Ohaus scales, the shot container part of the scale pan is what the factory uses to fine tune the scale to work correctly and adding or removing shot is the correct procedure to adjust the scale to zero correctly and adding or removing shot from it will not affect accuracy once you have it correctly zeroed with the foot roughly in the middle of it's adjustment. I bought a 510 scale off eBay around a decade or 2 ago to be a second scale to use with my 1010 scale. And when I received it, zero was off enough that I had to have the foot almost all the way at the end of the adjustment to get zero. I took the pan apart by removing the screw and separating the halves and removing 1 or 2 shot and solved the problem. And yes, I did check it with scale weights after.