ΔE 11.2, fair: the same colour family, but not a straight swap. Steel Legion Drab is more muted, warmer than RAL 6040 F9 Helloliv.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 11). Steel Legion Drab is more muted, warmer than RAL 6040 F9 Helloliv.
The same difference applies the other way round: RAL 6040 F9 Helloliv 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 RAL 6040 F9 Helloliv on the colour wheel See Steel Legion Drab on the colour wheel
All matches: RAL 6040 F9 Helloliv equivalents · Steel Legion Drab equivalents