ΔE 23.9, loose: different enough that you should pick on purpose. Yellow Green is a little lighter, much more saturated than Fall Green.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 24). Yellow Green is a little lighter, much more saturated than Fall Green.
The same difference applies the other way round: Fall Green is a little darker, 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 Fall Green on the colour wheel See Yellow Green on the colour wheel
All matches: Fall Green equivalents · Yellow Green equivalents