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