ΔE 12.8, fair: the same colour family, but not a straight swap. Skink Blue is noticeably darker than Light Sky Blue.
Can I use Skink Blue instead of Light Sky Blue?
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 13). Skink Blue is noticeably darker than Light Sky Blue.
Can I use Light Sky Blue instead of Skink Blue?
The same difference applies the other way round: Light Sky Blue is noticeably lighter.
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.