Discrepancy Hunting in Non-Biblical Literature: Couldn't Sallust just have made a mistake?

Today I'm continuing to discuss bad methodology as applied to non-biblical ancient history. Did Sallust deliberately move a saying by the conspirator Catiline to a different meeting with the Senate? First, we should consider the (actually not terribly implausible) possibility that Catiline was just fond of the sound of his own threat against Rome and that he used it on more than one occasion. But next, let's think about how easy it would have been for Sallust to make a mistake about when Catiline threatened to bring down Rome in "general ruin." Since precisely what is at issue is whether changing sayings to times when they didn't occur was a known and accepted "compositional device of the time," the literary device theorists can't assume that Sallust was likely to make such a deliberate change. That would be circular. Supposedly this incident in which Sallust makes this change is *evidence for* the existence of such a device. It's therefore a real problem when those making that argument are blind to the plausibility of more common causes of the discrepancy like ordinary error.