ΔE 6.2, close: similar, with a visible difference side by side. Ivory is a little darker, more muted than Bone.
Usually, if you are not matching paint already on the model. Close match (ΔE 6). Ivory is a little darker, more muted than Bone.
The same difference applies the other way round: Bone is a little lighter, more saturated.
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 Bone on the colour wheel See Ivory on the colour wheel
All matches: Bone equivalents · Ivory equivalents