ΔE 12.4, fair: the same colour family, but not a straight swap. Dark Jade is a little darker, more saturated, cooler than Mid Feldgrau.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 12). Dark Jade is a little darker, more saturated, cooler than Mid Feldgrau.
The same difference applies the other way round: Mid Feldgrau is a little lighter, 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 Mid Feldgrau on the colour wheel See Dark Jade on the colour wheel
All matches: Mid Feldgrau equivalents · Dark Jade equivalents