ΔE 19.1, loose: different enough that you should pick on purpose. Ultramarine Highlight is noticeably darker, warmer than Electric Blue.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 19). Ultramarine Highlight is noticeably darker, warmer than Electric Blue.
The same difference applies the other way round: Electric Blue is noticeably lighter, 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 Electric Blue on the colour wheel See Ultramarine Highlight on the colour wheel
All matches: Electric Blue equivalents · Ultramarine Highlight equivalents