ΔE 14.6, fair: the same colour family, but not a straight swap. Ivory Tusk is noticeably darker, more muted than Pearl Skin.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 15). Ivory Tusk is noticeably darker, more muted than Pearl Skin.
The same difference applies the other way round: Pearl Skin is noticeably lighter, 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 Pearl Skin on the colour wheel See Ivory Tusk on the colour wheel
All matches: Pearl Skin equivalents · Ivory Tusk equivalents