I'll join CNY bikeman in saying that a 1mm chainline error is totally meaningless in the scheme of things. If you think about it, the chainline varies by more than that simply because of slight spindle length, or crank position changes.

Odd are the hanger is off somewhat, though it's just as often a sluggish cable issue.

I'd start a diagnostic process by disconnecting th cable from the RD, and shift from high to 2nd high by pushing the lower body in. Then let go and it should snap back and shift cleanly. Adjust the limit until it does, and repeat that shift until it's consistent.

Connect the cable, adjust the trim and it should be just as crisp. If not, you know it's a cable related problem.