ΔE 15.6, loose: different enough that you should pick on purpose. Moon Yellow is noticeably darker, warmer than Primary Yellow.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 16). Moon Yellow is noticeably darker, warmer than Primary Yellow.
The same difference applies the other way round: Primary Yellow is noticeably lighter, cooler.
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 Primary Yellow on the colour wheel See Moon Yellow on the colour wheel
All matches: Primary Yellow equivalents · Moon Yellow equivalents