► To do what you describe, the beam has to have an element of friction induced by crud on the pivots, or rubbing out at the indicator end. The knives often appear not to be straight, but that has little effect since the gem stones "float" and find their own center under their stainless steel keepers.
► Don't forget that powder measures will vary more than a balance beam. You could in truth have 1 powder 'drop' that varies more than the previous 9, due to basic density or static issues. This is why I suggest powder measure averaging. For instance, if you desire 7.6gr per cartridge, then adjust your powder measure to 76.0gr with 10 "drops". Each individual 'drop' will be closer to 7.6gr, but none will ever be truly identical.
► Replacement parts mean absolutely zero IF the beam comes to a balance at 0 grains. That is the beauty of the balance beam design. No other special tools or techniques need be used IF the beam levels out when set to 0.
Hope this helps!