ΔE 9.5, close: similar, with a visible difference side by side. Parched Grass (Late) is a little lighter, more saturated than Ashen Grey.
Usually, if you are not matching paint already on the model. Close match (ΔE 9). Parched Grass (Late) is a little lighter, more saturated than Ashen Grey.
The same difference applies the other way round: Ashen 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 Ashen Grey on the colour wheel See Parched Grass (Late) on the colour wheel
All matches: Ashen Grey equivalents · Parched Grass (Late) equivalents