ΔE 10.7, fair: the same colour family, but not a straight swap. Dark Red is a little darker, cooler than Red Leather.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 11). Dark Red is a little darker, cooler than Red Leather.
The same difference applies the other way round: Red Leather 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 Red Leather on the colour wheel See Dark Red on the colour wheel
All matches: Red Leather equivalents · Dark Red equivalents