I think he's looking for the U.S. market nomenclature - to advertise a U.S. market car. We never had mushroom here - only creme beige and parchment. They are very similar but I don't think they are the same. I once laid a creme beige headrest on a parchment seat and there was a noticeable difference. Plus it would be unlike Mercedes to use two different names and color codes for the same color. A trip to the dealership can solve the mystery - to get the VMI and ask the parts counter to look up the upholstery code.