ΔE 19.8, loose: different enough that you should pick on purpose. Phalanx Yellow is more muted, warmer than Acid Green.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 20). Phalanx Yellow is more muted, warmer than Acid Green.
The same difference applies the other way round: Acid 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 Acid Green on the colour wheel See Phalanx Yellow on the colour wheel
All matches: Acid Green equivalents · Phalanx Yellow equivalents