ΔE 12.8, fair: the same colour family, but not a straight swap. Deep Green is noticeably lighter than Prussian Green.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 13). Deep Green is noticeably lighter than Prussian Green.
The same difference applies the other way round: Prussian Green is noticeably 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 Prussian Green on the colour wheel See Deep Green on the colour wheel
All matches: Prussian Green equivalents · Deep Green equivalents