ΔE 8.3, close: similar, with a visible difference side by side. Dark Imperial Khaki is a little lighter, more saturated, cooler than Grey-Green.
Usually, if you are not matching paint already on the model. Close match (ΔE 8). Dark Imperial Khaki is a little lighter, more saturated, cooler than Grey-Green.
The same difference applies the other way round: Grey-Green is a little darker, more muted, 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 Grey-Green on the colour wheel See Dark Imperial Khaki on the colour wheel
All matches: Grey-Green equivalents · Dark Imperial Khaki equivalents