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