ΔE 11.7, fair: the same colour family, but not a straight swap. Sapphire Blue is a little darker, more saturated, cooler than Dream On.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 12). Sapphire Blue is a little darker, more saturated, cooler than Dream On.
The same difference applies the other way round: Dream On is a little lighter, more muted, 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 Dream On on the colour wheel See Sapphire Blue on the colour wheel
All matches: Dream On equivalents · Sapphire Blue equivalents