ΔE 22.8, loose: different enough that you should pick on purpose. Yellow Green is noticeably darker, cooler than Light Mustard Khaki.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 23). Yellow Green is noticeably darker, cooler than Light Mustard Khaki.
The same difference applies the other way round: Light Mustard Khaki is noticeably lighter, 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 Light Mustard Khaki on the colour wheel See Yellow Green on the colour wheel
All matches: Light Mustard Khaki equivalents · Yellow Green equivalents