ΔE 20.9, loose: different enough that you should pick on purpose. Permanent Green Light is noticeably darker, more muted, cooler than Gauss Green.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 21). Permanent Green Light is noticeably darker, more muted, cooler than Gauss Green.
The same difference applies the other way round: Gauss Green is noticeably lighter, more saturated, warmer.
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 Gauss Green on the colour wheel See Permanent Green Light on the colour wheel
All matches: Gauss Green equivalents · Permanent Green Light equivalents