ΔE 14.5, fair: the same colour family, but not a straight swap. Parasite Brown is a little darker, more saturated, warmer than T'au Light Ochre.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 14). Parasite Brown is a little darker, more saturated, warmer than T'au Light Ochre.
The same difference applies the other way round: T'au Light Ochre is a little lighter, more muted, 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 T'au Light Ochre on the colour wheel See Parasite Brown on the colour wheel
All matches: T'au Light Ochre equivalents · Parasite Brown equivalents