ΔE 14.0, fair: the same colour family, but not a straight swap. Flanker Blue is a little lighter, more saturated than Ash Grey.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 14). Flanker Blue is a little lighter, more saturated than Ash Grey.
The same difference applies the other way round: Ash Grey is a little darker, 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 Ash Grey on the colour wheel See Flanker Blue on the colour wheel
All matches: Ash Grey equivalents · Flanker Blue equivalents