Some of the top battles are strangely ordered. Anyway, PoD Bane even by novel's end didn't have the knowledge to face a fully learned Sadow in all-out combat. Assuming that he matches him in sabers, there's still the issue of Sadow's capability with Force Illusions and at peak him being able to work through the Force to generate supernovas and solar flares. No way Bane at that point was ready to engage with that kind of ability. He did counter Kaan's mental hold, but I don't think that quite compares to what Sadow would unleash if he were trying to kill Bane.