ΔE 11.3, fair: the same colour family, but not a straight swap. Dark Green is a little darker, more muted, cooler than Dark Mustard Khaki.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 11). Dark Green is a little darker, more muted, cooler than Dark Mustard Khaki.
The same difference applies the other way round: Dark Mustard Khaki is a little lighter, 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 Dark Mustard Khaki on the colour wheel See Dark Green on the colour wheel
All matches: Dark Mustard Khaki equivalents · Dark Green equivalents