ΔE 30.2, loose: different enough that you should pick on purpose. Indigo Sky is noticeably darker, cooler than Dechala Lilac.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 30). Indigo Sky is noticeably darker, cooler than Dechala Lilac.
The same difference applies the other way round: Dechala Lilac is noticeably 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 Dechala Lilac on the colour wheel See Indigo Sky on the colour wheel
All matches: Dechala Lilac equivalents · Indigo Sky equivalents