ΔE 7.7, close: similar, with a visible difference side by side. Cayman Green is a little darker, more saturated than Mid Mustard Khaki.
Usually, if you are not matching paint already on the model. Close match (ΔE 8). Cayman Green is a little darker, more saturated than Mid Mustard Khaki.
The same difference applies the other way round: Mid Mustard Khaki 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 Mid Mustard Khaki on the colour wheel See Cayman Green on the colour wheel
All matches: Mid Mustard Khaki equivalents · Cayman Green equivalents