ΔE 11.9, fair: the same colour family, but not a straight swap. Deep Sky Blue is cooler than Faded Ultramarine.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 12). Deep Sky Blue is cooler than Faded Ultramarine.
The same difference applies the other way round: Faded Ultramarine is 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 Faded Ultramarine on the colour wheel See Deep Sky Blue on the colour wheel
All matches: Faded Ultramarine equivalents · Deep Sky Blue equivalents