[Morthoron]

Tolkien's inconsistencies are usually attributible to his incessant dawdling with the story. He writes, then rewrites, edits the rewrites and then writes the whole thing over again. Some of the old material remains with the rewritten material, and over time there are strata of story molded into a coherent whole. It's rather like the whole process of oral mythology eventually conglomerating into printed form, except writ small by a single author over decades, when the usal process takes centuries.