' But here in Imladris we have what he left us--and what later came to us copied by Numenorean hands, in the hold of Numenorean ships, and last of all in that small desperate fleet of Elendil's. It may not even be as complete and reliable an account as Pengolodh himself would have made it ...' '

Yes, yes! Not only does this address the problems of authorship in the canon, it explains some of the discrepancies. I've always thought Bilbo's 'final' result was something like the game of telephone. A crucial word missed in this copy, a mistranslation in that one, and the story can change dramatically.
(erunyauve, too lazy to log in)