Psychic Shock vs Scaly Highlight

How close are they?

ΔE 16.1, loose: different enough that you should pick on purpose. Scaly Highlight is noticeably darker, more saturated, warmer than Psychic Shock.

Can I use Scaly Highlight instead of Psychic Shock?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 16). Scaly Highlight is noticeably darker, more saturated, warmer than Psychic Shock.

Can I use Psychic Shock instead of Scaly Highlight?

The same difference applies the other way round: Psychic Shock is noticeably lighter, more muted, 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.