ΔE 8.8, close: similar, with a visible difference side by side. Buff is a little darker, more saturated than Dark Sand.
Usually, if you are not matching paint already on the model. Close match (ΔE 9). Buff is a little darker, more saturated than Dark Sand.
The same difference applies the other way round: Dark Sand is a little lighter, more muted.
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 Sand on the colour wheel See Buff on the colour wheel
All matches: Dark Sand equivalents · Buff equivalents