ΔE 16.0, loose: different enough that you should pick on purpose. Quinacridone Red Light is warmer than Evil Sunz Scarlet.
Can I use Quinacridone Red Light instead of Evil Sunz Scarlet?
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 16). Quinacridone Red Light is warmer than Evil Sunz Scarlet.
Can I use Evil Sunz Scarlet instead of Quinacridone Red Light?
The same difference applies the other way round: Evil Sunz Scarlet is 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.