ΔE 16.4, loose: different enough that you should pick on purpose. Amethyst Purple is noticeably darker, more muted, cooler than Dechala Lilac.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 16). Amethyst Purple is noticeably darker, more muted, cooler than Dechala Lilac.
The same difference applies the other way round: Dechala Lilac is noticeably lighter, more saturated, 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 Amethyst Purple on the colour wheel
All matches: Dechala Lilac equivalents · Amethyst Purple equivalents