ΔE 9.1, close: similar, with a visible difference side by side. Sky Type S is a little lighter, more muted, warmer than Cockpit Green (IJN).
Usually, if you are not matching paint already on the model. Close match (ΔE 9). Sky Type S is a little lighter, more muted, warmer than Cockpit Green (IJN).
The same difference applies the other way round: Cockpit Green (IJN) is a little darker, more saturated, 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 Cockpit Green (IJN) on the colour wheel See Sky Type S on the colour wheel
All matches: Cockpit Green (IJN) equivalents · Sky Type S equivalents