ΔE 59.7, loose: different enough that you should pick on purpose. Ink Green is noticeably darker, much more saturated than Light Grey.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 60). Ink Green is noticeably darker, much more saturated than Light Grey.
The same difference applies the other way round: Light Grey is noticeably lighter, much more muted.
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 Light Grey on the colour wheel See Ink Green on the colour wheel
All matches: Light Grey equivalents · Ink Green equivalents