Need another mechanic tip: lower ball joint studs turning with nuts?

Mine uses low profile hex head bolts. Why does there appear to be a washer between the spindle and ball joint?

I was researching that when I found this thread. I'm trying to tune my front suspension and can't get negative camber on one side. Someone suggested adding 1/8" washers between the ball joint casting and spindle to tilt the wheel in. I'm thinking about trying it.