ΔE 6.8, close: similar, with a visible difference side by side. Gray Violet is a little lighter than Ultimate Cup of Coffee.
Usually, if you are not matching paint already on the model. Close match (ΔE 7). Gray Violet is a little lighter than Ultimate Cup of Coffee.
The same difference applies the other way round: Ultimate Cup of Coffee is a little darker.
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 Ultimate Cup of Coffee on the colour wheel See Gray Violet on the colour wheel
All matches: Ultimate Cup of Coffee equivalents · Gray Violet equivalents