ΔE 10.1, fair: the same colour family, but not a straight swap. Flat White is a little lighter, more muted than Skyshard.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 10). Flat White is a little lighter, more muted than Skyshard.
The same difference applies the other way round: Skyshard is a little darker, 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 Skyshard on the colour wheel See Flat White on the colour wheel
All matches: Skyshard equivalents · Flat White equivalents