ΔE 8.9, close: similar, with a visible difference side by side. White Grey is a little darker, more muted, cooler than Fair Highlights.
Usually, if you are not matching paint already on the model. Close match (ΔE 9). White Grey is a little darker, more muted, cooler than Fair Highlights.
The same difference applies the other way round: Fair Highlights is a little lighter, more saturated, warmer.
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 Fair Highlights on the colour wheel See White Grey on the colour wheel
All matches: Fair Highlights equivalents · White Grey equivalents