ΔE 9.5, close: similar, with a visible difference side by side. Bony Spikes is a little darker, more saturated than Offwhite.
Usually, if you are not matching paint already on the model. Close match (ΔE 10). Bony Spikes is a little darker, more saturated than Offwhite.
The same difference applies the other way round: Offwhite is a little lighter, 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 Offwhite on the colour wheel See Bony Spikes on the colour wheel
All matches: Offwhite equivalents · Bony Spikes equivalents