Killfist,
I align with Xenon, SSDR, and Michael Chandra.
However, you might be missing the forest for the trees.
Just look at this like math or calculus.
Essence is a variable.
You Sorcery roll is a variable
(Sorcery test successes) - (5-essence) = X
If I have an essence 6, then my threshold is -1. Meaning the "-(-1)" part becomes "+1".
If I cast the spell, and I get 0 (Zero/No hits), then doing the math the same as I would any other essence value gives me 1 net hit.
Best,
SL