ΔE 9.8, close: similar, with a visible difference side by side. Heavy Warm White is more saturated than Wrack White.
Usually, if you are not matching paint already on the model. Close match (ΔE 10). Heavy Warm White is more saturated than Wrack White.
The same difference applies the other way round: Wrack White is 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 Wrack White on the colour wheel See Heavy Warm White on the colour wheel
All matches: Wrack White equivalents · Heavy Warm White equivalents