ΔE 17.8, loose: different enough that you should pick on purpose. Flubber Green is a little darker, much more saturated than Gauss Green.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 18). Flubber Green is a little darker, much more saturated than Gauss Green.
The same difference applies the other way round: Gauss Green is a little 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 Gauss Green on the colour wheel See Flubber Green on the colour wheel
All matches: Gauss Green equivalents · Flubber Green equivalents