It's interesting to speculate about these things but I expect the real world reason is that Steve just changed his mind somewhere along the way. When he wrote Taltos, he had one idea of Morollan's background and when he wrote Lord of Castle Black he had a different one or one that was more fleshed out than previously. Likewise, the comments about sorcery when it technically shouldn't have been possbile anywhere. Steve changed the rules. In the early books, the Orb is a kind of facilitator. That is, it makes sorcery EASY rather than making it possible. I'd have to go through the books to find the references, but I'm pretty sure there are places where Vlad comments about innovations like teleportation and revivifiation occuring post-Interregnum because the few Wizards and such who were able to practice sorcery during the Interregnum had to invent new ways of doing things. Once the Orb returned, those innovations spread to everyone and akin to the Industrial Revolution that was mentioned earlier, new sorcerous invention continued at an even faster pace. In the most recent books we instead have the Orb becoming New and Improved thanks to the Gods and innovations happening as a direct consquence of its increased power. (This in turn suggests that the Lords of Judgement are deliberately regulating the amount of sorcery available to the Empire but that's another matter.) Now most authors would deal with these little lapses and inconsistencies by either ignoring them or writing (oft-times convoluted) justifications for them. Steve's chosen the more interesting route of embracing them and shifting the blame to the unreliability of his narrators instead, to the point of deliberately inserting "cracks and shards" into the stories just to keep us readers guessing about what is actually the true story. (Perhaps also to illustrate the fact that in an imperfect world you seldom know the complete and "true" version of any particular event. You only know what the historian chooses to talk about.) Vlad worries that his memories are tampered with. Morollan's version of an event completely contradicts Paarfi's. Paarfi also contradicts other known sources. Paarfi's version of what appears to be Paresh's story doesn't include a running sorcery battle between Aerich and Paresh. However, Paafi plainly states that a gentleman wouldn't condescend to honor a peasant by acknowledging him in such a manner, so his reporting is suspect. We don't know if he's reporting on the actual events or if he's reporting his "romantic" version of events. Additionally, Paarfi's character is, well, questionable let's say so his reliability as a purveyor of absolute truth is questionable as well. Sorcery during the Interregnum becomes attributed to Pre-Empire sorcery which is outlawed and confined to the knowledge of a handful of specialists,yet simultaneously seems to be known about and practiced by a rather large number of people. Ditto the Jenoine. The Empire at large doesn't know about them, yet any given character in a story accepts their existence matter of factly and is even educated in ways of dealing with them. Basically, Dragaera is an exercise in contradictions and choosing which ones to believe pretty much comes down to choosing which narrator you're willing to rely on.