ΔE 9.9, close: similar, with a visible difference side by side. Medium Yellow is a little darker than Moonbeam Yellow.
Usually, if you are not matching paint already on the model. Close match (ΔE 10). Medium Yellow is a little darker than Moonbeam Yellow.
The same difference applies the other way round: Moonbeam Yellow is a little lighter.
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 Moonbeam Yellow on the colour wheel See Medium Yellow on the colour wheel
All matches: Moonbeam Yellow equivalents · Medium Yellow equivalents