Burnt Orange vs Flat Flesh

How close are they?

ΔE 7.9, close: similar, with a visible difference side by side. Flat Flesh is a little lighter than Burnt Orange.

Can I use Flat Flesh instead of Burnt Orange?

Usually, if you are not matching paint already on the model. Close match (ΔE 8). Flat Flesh is a little lighter than Burnt Orange.

Can I use Burnt Orange instead of Flat Flesh?

The same difference applies the other way round: Burnt Orange 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.