ΔE 15.7, loose: different enough that you should pick on purpose. Underhive Ash is more muted, warmer than Interior Light Green.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 16). Underhive Ash is more muted, warmer than Interior Light Green.
The same difference applies the other way round: Interior Light Green is 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 Interior Light Green on the colour wheel See Underhive Ash on the colour wheel
All matches: Interior Light Green equivalents · Underhive Ash equivalents