ΔE 8.8, close: similar, with a visible difference side by side. A-28M Greyish Blue is a little darker, more saturated, cooler than A-18f Light Grey-Blue.
Usually, if you are not matching paint already on the model. Close match (ΔE 9). A-28M Greyish Blue is a little darker, more saturated, cooler than A-18f Light Grey-Blue.
The same difference applies the other way round: A-18f Light Grey-Blue is a little lighter, more muted, 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 A-18f Light Grey-Blue on the colour wheel See A-28M Greyish Blue on the colour wheel
All matches: A-18f Light Grey-Blue equivalents · A-28M Greyish Blue equivalents