ΔE 8.6, close: similar, with a visible difference side by side. IJA Khaki Brown is a little lighter, more muted, warmer than Dark Green Brown.
Usually, if you are not matching paint already on the model. Close match (ΔE 9). IJA Khaki Brown is a little lighter, more muted, warmer than Dark Green Brown.
The same difference applies the other way round: Dark Green Brown is a little darker, more saturated, cooler.
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 Green Brown on the colour wheel See IJA Khaki Brown on the colour wheel
All matches: Dark Green Brown equivalents · IJA Khaki Brown equivalents