what is the meaning of "non" in this sentence?

Cicero signals his intention to begin his philosophical discussion by reviewing Epicureanism.

Ut autem a facillimis ordiamur, prima veniat in medium Epicuri ratio, quae plerisque notissima est. quam a nobis sic intelleges expositam, ut ab ipsis, qui eam disciplinam probant, non soleat accuratius explicari;

Translation: In order to begin with the easiest, we place in review the theory of Epicurus, which is the best known to the majority. Here you will see Epicureanism set forth as accurately as it usually is by those who approve this doctrine.

In translating I overlooked “non”, because it’s hard to believe that Cicero would begin by saying that Epicureanism is not usually explained accurately by its own adherents.

But it has to mean something, and I don’t know what that may be.

The idea is: the adherents of Epicureanism don’t explain it more accurately than I will.

“You will see it explained by me in such a way that (result clause) it is not usually explained more accurately by those who approve of this doctrine.”

“not more accurately”: got it! Comparative adverb. Hopefully I’ll see this next time!

Thanks Qimmik.