ΔE 7.6, close: similar, with a visible difference side by side. Dark Prussian Blue is a little darker, more saturated, warmer than Chancellor Blue.
Usually, if you are not matching paint already on the model. Close match (ΔE 8). Dark Prussian Blue is a little darker, more saturated, warmer than Chancellor Blue.
The same difference applies the other way round: Chancellor Blue is a little lighter, more muted, cooler.
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 Chancellor Blue on the colour wheel See Dark Prussian Blue on the colour wheel
All matches: Chancellor Blue equivalents · Dark Prussian Blue equivalents