ΔE 13.0, fair: the same colour family, but not a straight swap. Flat Green is noticeably lighter, warmer than Hierotek Green.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 13). Flat Green is noticeably lighter, warmer than Hierotek Green.
The same difference applies the other way round: Hierotek Green is noticeably darker, 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 Hierotek Green on the colour wheel See Flat Green on the colour wheel
All matches: Hierotek Green equivalents · Flat Green equivalents