ΔE 12.4, fair: the same colour family, but not a straight swap. Plague Brown is noticeably darker, more saturated than Phoenix Flames.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 12). Plague Brown is noticeably darker, more saturated than Phoenix Flames.
The same difference applies the other way round: Phoenix Flames is noticeably lighter, more muted.
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 Phoenix Flames on the colour wheel See Plague Brown on the colour wheel
All matches: Phoenix Flames equivalents · Plague Brown equivalents