ΔE 14.4, fair: the same colour family, but not a straight swap. Pastel Green is noticeably lighter than Dark Imperial Khaki.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 14). Pastel Green is noticeably lighter than Dark Imperial Khaki.
The same difference applies the other way round: Dark Imperial Khaki is noticeably darker.
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 Imperial Khaki on the colour wheel See Pastel Green on the colour wheel
All matches: Dark Imperial Khaki equivalents · Pastel Green equivalents