Color code for Ivory?

I had Rich Maroon done off of the Museum formula and it came out wrong too - pinkish/purple cast to it that was not appealing in sunlight

I have the color code for Ivory from the ACD museum and just had my local paint shop mix up a can. As you can see in the photo below, it turned out more yellow than it is supposed to be. Does anyone know where I can get a correct "modern" paint code for Cord Ivory?