ΔE 11.7, fair: the same colour family, but not a straight swap. Pastel Yellow is a little darker, more muted than High Coverage Yellow. They are different kinds of paint: AMMO by Mig High Coverage Yellow is an opaque base/layer paint and Army Painter Pastel Yellow is a one-coat contrast-style paint, so they won’t behave the same on the model even where the colour is close.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 12). Pastel Yellow is a little darker, more muted than High Coverage Yellow. They are different kinds of paint.
The same difference applies the other way round: High Coverage Yellow is a little lighter, more saturated.
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 High Coverage Yellow on the colour wheel See Pastel Yellow on the colour wheel
All matches: High Coverage Yellow equivalents · Pastel Yellow equivalents