ΔE 4.4, very close: most people won’t see a difference side by side. Prussian Blue Hue is a little darker than Dark Blue Tone. They are different kinds of paint: Army Painter Dark Blue Tone is a wash/shade and Golden Prussian Blue Hue is an opaque base/layer paint, so they won’t behave the same on the model even where the colour is close.
Yes, for most jobs. Very close match (ΔE 4). Prussian Blue Hue is a little darker than Dark Blue Tone. They are different kinds of paint.
The same difference applies the other way round: Dark Blue Tone 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 Dark Blue Tone on the colour wheel See Prussian Blue Hue on the colour wheel
All matches: Dark Blue Tone equivalents · Prussian Blue Hue equivalents