ΔE 8.5, close: similar, with a visible difference side by side. Mid Mustard Khaki is more saturated than RAL 7028 Dunkelgelb (Initial).
Usually, if you are not matching paint already on the model. Close match (ΔE 8). Mid Mustard Khaki is more saturated than RAL 7028 Dunkelgelb (Initial).
The same difference applies the other way round: RAL 7028 Dunkelgelb (Initial) is 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 RAL 7028 Dunkelgelb (Initial) on the colour wheel See Mid Mustard Khaki on the colour wheel
All matches: RAL 7028 Dunkelgelb (Initial) equivalents · Mid Mustard Khaki equivalents