Mythical Orange vs Peach Flesh

How close are they?

ΔE 16.1, loose: different enough that you should pick on purpose. Peach Flesh is noticeably lighter, more muted, warmer than Mythical Orange.

Can I use Peach Flesh instead of Mythical Orange?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 16). Peach Flesh is noticeably lighter, more muted, warmer than Mythical Orange.

Can I use Mythical Orange instead of Peach Flesh?

The same difference applies the other way round: Mythical Orange is noticeably 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.