I was surprised you didn't warn me earlier. I was waiting for it. I know it's not uncommon to confuse them so I would have made the same point if I were to recommend it.
It's only been 8 months since I updated this. Shame on me.
In any case the nitrofurazone/chloramphenicol treatment did not work. The ulcers return at the same rate. So, I will try Coryloach's recommendation of flubendazole soon. Seems not to be bacterial, or it is just incurable through antibiotics. Fish is still in it's own 55G doing well otherwise.