I’m having a simular problem.
I have a folder with various Albums. Autotaging seems to recognize the Albums, because it rewrites the Album name for example from High (from the Cure) to High [UK Import], but it doesn’t add the Title. Covers are also downloaded as well as Song text. Don’t understand this behaviour.
Any hints would be greatly appreciated as I too have an enourmous amount of files I would like to tag.