ΔE 10.8, fair: the same colour family, but not a straight swap. Stormvermin Fur is noticeably darker, cooler than Matt Dirt. They are different kinds of paint: AMMO by Mig Matt Dirt is an ink, glaze or transparent paint and Citadel Stormvermin Fur is an opaque base/layer paint, so they won’t behave the same on the model even where the colour is close.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 11). Stormvermin Fur is noticeably darker, cooler than Matt Dirt. They are different kinds of paint.
The same difference applies the other way round: Matt Dirt is noticeably 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 Matt Dirt on the colour wheel See Stormvermin Fur on the colour wheel
All matches: Matt Dirt equivalents · Stormvermin Fur equivalents