ΔE 11.4, fair: the same colour family, but not a straight swap. Mahogany Brown is a little lighter, more muted, warmer than Black Skintone.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 11). Mahogany Brown is a little lighter, more muted, warmer than Black Skintone.
The same difference applies the other way round: Black Skintone is a little darker, more saturated, 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 Black Skintone on the colour wheel See Mahogany Brown on the colour wheel
All matches: Black Skintone equivalents · Mahogany Brown equivalents