Looking at the pictures, it looks more like a part which did quite not meet design fitment specs, meaning the part clipped into place securely, but there are visible gaps. Hence poor fit and finish. Just like you would see brand new cars with the hood and fender gap not being uniform between the left side and right side of the hood. There is nothing to really adjust, just poor fit and finish. Not sure what you can wiggle out of the Mercedes folks here.