ΔE 9.4, close: similar, with a visible difference side by side. Flat Earth is more muted, warmer than Red Leather.
Usually, if you are not matching paint already on the model. Close match (ΔE 9). Flat Earth is more muted, warmer than Red Leather.
The same difference applies the other way round: Red Leather is 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 Red Leather on the colour wheel See Flat Earth on the colour wheel
All matches: Red Leather equivalents · Flat Earth equivalents