ΔE 7.1, close: similar, with a visible difference side by side. Dark Vermilion is a little darker than Reddish Orange.
Usually, if you are not matching paint already on the model. Close match (ΔE 7). Dark Vermilion is a little darker than Reddish Orange.
The same difference applies the other way round: Reddish Orange is a little lighter.
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 Reddish Orange on the colour wheel See Dark Vermilion on the colour wheel
All matches: Reddish Orange equivalents · Dark Vermilion equivalents