ΔE 10.6, fair: the same colour family, but not a straight swap. Pale Sand is a little darker, cooler than Flat Flesh.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 11). Pale Sand is a little darker, cooler than Flat Flesh.
The same difference applies the other way round: Flat Flesh is a little lighter, 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 Flat Flesh on the colour wheel See Pale Sand on the colour wheel
All matches: Flat Flesh equivalents · Pale Sand equivalents