ΔE 9.6, close: similar, with a visible difference side by side. Grey Blue is a little darker, more saturated than Darkness Grey.
Usually, if you are not matching paint already on the model. Close match (ΔE 10). Grey Blue is a little darker, more saturated than Darkness Grey.
The same difference applies the other way round: Darkness Grey is a little lighter, 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 Darkness Grey on the colour wheel See Grey Blue on the colour wheel
All matches: Darkness Grey equivalents · Grey Blue equivalents