ΔE 12.2, fair: the same colour family, but not a straight swap. Warm Yellow is a little darker, warmer than Phalanx Yellow.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 12). Warm Yellow is a little darker, warmer than Phalanx Yellow.
The same difference applies the other way round: Phalanx Yellow is a little lighter, 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 Phalanx Yellow on the colour wheel See Warm Yellow on the colour wheel
All matches: Phalanx Yellow equivalents · Warm Yellow equivalents