ΔE 10.8, fair: the same colour family, but not a straight swap. Griffon Blue is a little darker, more muted than Mediterranean Blue.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 11). Griffon Blue is a little darker, more muted than Mediterranean Blue.
The same difference applies the other way round: Mediterranean Blue 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 Mediterranean Blue on the colour wheel See Griffon Blue on the colour wheel
All matches: Mediterranean Blue equivalents · Griffon Blue equivalents