ΔE 14.8, fair: the same colour family, but not a straight swap. Buff is a little lighter, more saturated, warmer than Krieg Khaki.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 15). Buff is a little lighter, more saturated, warmer than Krieg Khaki.
The same difference applies the other way round: Krieg Khaki is a little darker, more muted, 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 Krieg Khaki on the colour wheel See Buff on the colour wheel
All matches: Krieg Khaki equivalents · Buff equivalents