ΔE 10.4, fair: the same colour family, but not a straight swap. Flat Red is a little lighter, more muted than Quinacridone Violet.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 10). Flat Red is a little lighter, more muted than Quinacridone Violet.
The same difference applies the other way round: Quinacridone Violet is a little darker, more saturated.
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 Quinacridone Violet on the colour wheel See Flat Red on the colour wheel
All matches: Quinacridone Violet equivalents · Flat Red equivalents