As far as I know getting good compatability is a case by case job. I'm going by the set up at the Mercedes dealer in Athens Ga. They've got a guy there with 30 something years experience and he blends his own paint to make it look good with what you have on your car. I'm sure he starts with a color code number.
So he's doing some mixing, then if he's doing a fender for example he sprays over into the adjoining door area and makes a transition if one is needed so you don't have that jump in color value from one section to the next.
The body shop manager explained to me that insurance companies are starting to cover this extra work so I imagine many shops can do it.
My main point was that it's worth taking the time to find somebody that can do this well and talk to them about the process (what kind of paint, how many coats, how the new paint is different from the factory paint) because you want to know how the car is going to look in a year, not just when it comes back from the paint shop.
Harvey