I tried to look at both, they are similar except I find the plume more orangey.

colors on monitors vary so much; if you google either paint color name, it pulls up discussions on both from this forum.

http://www.buyaurapaint.com/sw-6127.html

the above link shows a sample
of ivoire, they say pittsfield bluff is a close match; I seem to remember
some people here having used this color.

Here is a link that might be useful: feather plume

If you go to colorcharts.org and bring up feather plume, the BM color that's is a 92.5% match is 0156 Sweet Nectar. Don't know if that helps you or not.

Here is a link that might be useful: colorcharts