ΔE 10.7, fair: the same colour family, but not a straight swap. Deep Sky is a little darker, cooler than Indigo.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 11). Deep Sky is a little darker, cooler than Indigo.
The same difference applies the other way round: Indigo is a little lighter, 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 Indigo on the colour wheel See Deep Sky on the colour wheel
All matches: Indigo equivalents · Deep Sky equivalents