Here are the hue/value/chroma color notations for many of the colors on the SW strip. Just because colors are on the same strip is no guarantee that they will indeed harmonize and/or in the same hue family. Incredible White - 1.59Y hue/ 9 value / 1 chroma Agreeable Gray - 2.34Y hue / 8 value / 1 chroma Anew Gray - 1.52Y hue / 7 value / 1 chroma Mega Greige - 9.96YR hue / 7 value / 1 chroma Anonymous - 2.89Y hue / 5 value / 1 chroma Mega Greige belongs to the Yellow-Red hue family (orange) Given the above information, I would agree with nosoccermom that SW Anonymous might be the better choice to coordinate with Incredible White, Anew and Agreeable Gray. Because Mega Greige's notation indicates it could have orange overtones. I'll attach a color wheel so you can plot the colors according to hue family if you want to. P.S. Many people are unable to perceive the difference between pink overtones and orange overtones and will confuse pinkish and peachiness. It's important to know if the color characteristic is indeed pink (red hue family) or peach (orange hue family) because the light never gets confused - the light is boss. So you have to KNOW what hue family a color belongs to. And you KNOW what hue family a color belongs to by measuring it to capture its spectral data (its fingerprint or DNA) and converting that spectral data into a color notation - a hue/value/chroma notation.

I should add that I had painted Agreeable Gray on a poster board first and thought I found the perfect color. Then it looked totally different actually up on my walls :(

Same color would be pretty - and easy. When you cut or adjust a formula, you're creating a completely different color. Every dimension of the color is changed, hue, value, chroma, LRV. The new color might resemble the old color in some way, but there's no way to know until you have it mixed, dry it out and look at it. In the case of Agreeable Gray specifically, if you cut it by 50% you get a light gray that looks a lot like SW 6000 Snowfall. Agreeable Gray and Snowfall don't look good together - they don't "go" together. If you want a color that looks like Agreeable Gray, just lighter try White Heron SW 7627 for the ceiling. If you pull all three chips, Agreeably Gray, Snowfall and White Heron, you'll see what I'm talking about.

I have anew gray currently in my bedroom on the walls and alabaster on the trim. I think it would be beautiful to have the trim and perhaps the door also sw anew gray and the walls alabaster. Another look depending on the height of your ceilings, you could paint the ceiling anew gray with alabaster walls.