ΔE 7.5, close: similar, with a visible difference side by side. IJN Ash Grey is a little darker, cooler than Dusty Skull.
Usually, if you are not matching paint already on the model. Close match (ΔE 7). IJN Ash Grey is a little darker, cooler than Dusty Skull.
The same difference applies the other way round: Dusty Skull is a little lighter, 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 Dusty Skull on the colour wheel See IJN Ash Grey on the colour wheel
All matches: Dusty Skull equivalents · IJN Ash Grey equivalents