ΔE 10.6, fair: the same colour family, but not a straight swap. Dark Gray is more muted, cooler than Deep Azure.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 11). Dark Gray is more muted, cooler than Deep Azure.
The same difference applies the other way round: Deep Azure is more saturated, warmer.
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.
See Deep Azure on the colour wheel See Dark Gray on the colour wheel
All matches: Deep Azure equivalents · Dark Gray equivalents