ΔE 29.5, loose: different enough that you should pick on purpose. Magi Purple Wash is noticeably lighter, more muted, warmer than Dark Blue Tone.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 30). Magi Purple Wash is noticeably lighter, more muted, warmer than Dark Blue Tone.
The same difference applies the other way round: Dark Blue Tone is noticeably darker, more saturated, cooler.
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 Dark Blue Tone on the colour wheel See Magi Purple Wash on the colour wheel
All matches: Dark Blue Tone equivalents · Magi Purple Wash equivalents