ΔE 8.9, close: similar, with a visible difference side by side. US Earth Brown is a little lighter than Dark Neutral Grey.
Usually, if you are not matching paint already on the model. Close match (ΔE 9). US Earth Brown is a little lighter than Dark Neutral Grey.
The same difference applies the other way round: Dark Neutral Grey is a little darker.
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 Dark Neutral Grey on the colour wheel See US Earth Brown on the colour wheel
All matches: Dark Neutral Grey equivalents · US Earth Brown equivalents