Ran into the same issues as Adam, EPA VOC change (solvent vs water based) made OE paint formulas almost useless
My friend owns a Euro.Dealership and a white restored Pantera. After much deliberation and pressure to pick a color. I lazily relied on his research ( besides, any side by side pictures should look pretty cool ) I decided to go with the same color on my 72. My original paint was so bad I didn't have anything to go by. Im not sure of accuracy but I love it. (Not sure but I think OE color was not as bright)
FYI The base primer color slightly effected the shade on my test panels but, your mileage may vary.
Hope this helps
Mercedes Benz-9960 Alabasterweis