ΔE 11.2, fair: the same colour family, but not a straight swap. Rainy Gray is noticeably lighter than Dawnstone.
Can I use Rainy Gray instead of Dawnstone?
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 11). Rainy Gray is noticeably lighter than Dawnstone.
Can I use Dawnstone instead of Rainy Gray?
The same difference applies the other way round: Dawnstone is noticeably darker.
ΔE is the colour difference between our two swatch estimates: under about 6 is close, over about 15 is loose. Real paints also differ in finish, coverage and how they thin, so test before you commit.