ΔE 15.1, loose: different enough that you should pick on purpose. Typhon Ash is a little lighter, much more muted than Dark Imperial Khaki.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 15). Typhon Ash is a little lighter, much more muted than Dark Imperial Khaki.
The same difference applies the other way round: Dark Imperial Khaki is a little darker, much more saturated.
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 Typhon Ash on the colour wheel
All matches: Dark Imperial Khaki equivalents · Typhon Ash equivalents