I worked at tire shop one college summer. I remember the balancer you could set to static or dynamic...and that would balance it based on weight being only on the inside of the wheel or both...or you could set it to dynamic with was tell me where the weight needs to go and how much.
From there weight installation also mattered. The heavier ones can get pretty long and centering em up nice matter...grease monkeys just hammer em in ballpark location, then it calls for more weight, then they half aimed hammer in more...so on and so forth..next thing you know it's caked in weights.
Some wheels only allow weights on the inside, or just to maintain look of fancy wheels, guys will demand that.
Just like most things, it's not rocket science, yet lack of attention to details will bone you.