ΔE 11.1, fair: the same colour family, but not a straight swap. Blue Horror is a little lighter, more muted, cooler than Grey-Blue.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 11). Blue Horror is a little lighter, more muted, cooler than Grey-Blue.
The same difference applies the other way round: Grey-Blue is a little darker, more saturated, warmer.
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 Grey-Blue on the colour wheel See Blue Horror on the colour wheel
All matches: Grey-Blue equivalents · Blue Horror equivalents