ΔE 7.5, close: similar, with a visible difference side by side. Pastel Blue is a little lighter, warmer than Ashen Blue.
Usually, if you are not matching paint already on the model. Close match (ΔE 8). Pastel Blue is a little lighter, warmer than Ashen Blue.
The same difference applies the other way round: Ashen Blue is a little darker, 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 Ashen Blue on the colour wheel See Pastel Blue on the colour wheel
All matches: Ashen Blue equivalents · Pastel Blue equivalents