ΔE 7.2, close: similar, with a visible difference side by side. Flat Flesh is a little lighter than Medium Flesh Tone.
Usually, if you are not matching paint already on the model. Close match (ΔE 7). Flat Flesh is a little lighter than Medium Flesh Tone.
The same difference applies the other way round: Medium Flesh Tone is a little darker.
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 Medium Flesh Tone on the colour wheel See Flat Flesh on the colour wheel
All matches: Medium Flesh Tone equivalents · Flat Flesh equivalents