Next time when your at dealer have your SA do paint depth check on the painted/repaired surfaces. BMW Spec is 3.5-4mills on paint thickness to metal/plastic. Just kind of curious how thick paint is on your fix.
Honestly I can believe they wanted 5.5k for that repair at bmw, But I tell you one thing...My car has 2 panels that are repainted which was done at bmw collision and they did a amazing job for previous owner. Paint is PERFECTLY matched absolutely factory perfect. Only reason I found out those 2 areas where repainted is SA took paint gauge to car and one front fender and one rear fender where 5.5-6mills he looked at paper work on car from bmw and said it was painted at bmw collision center.
If you want it done right...bmw collision is where its at. (Not saying yours wasnt done good, just stating my experience.)