They should be able to match any SW color at Benjamin Moore

but gray owl, stonington gray, and revere pewter are all popular

Ps according to http://encycolorpedia.com/d0cec0, these are the closest BM colors to sedate gray

Your painter can have BM color match sedate gray which is really is a very soft green/ gray. BM sweet spring is very close but a tad lighter. Gray owl is a gray/ green that is a chameleon color that can read very differently depending on room orientation and lighting. Stingray a tad grayed but a nice color.