[Maédhros]

5. Information in sources of lower level priority are to be preferred over information in sources of higher level priority where the item of information in source of higher level priority can be reasonably demonstrated to be an error, whether a "slip of the pen" or from inadequate checking of previous writing.

Could you clarify this please?

6. The actual words used by J.R.R. Tolkien or the editor or summarizer of his work may only be changed, including change by deletion or addition, when:
a) they are minimally changed to agree with statements elsewhere in the canon recognized as of greater validity or to are replaced with words or phrases from later or alternate restatements of the same material for reasons of consistancy or are changed to agree with alternate phrasings used by Tolkien of the same or better validity

I wanted to point out your response Aiwendil to my suggestion of changing the phrase Children of Ilúvatar to Men or Children of Men:

I think it was quite likely a slip of the pen, though it's also quite possible that Tolkien was reconsidering the fate of the Elves. I'm a bit wary about changing it. Anyway, "Children of Iluvatar" could refer to both Elves and Men, or it could refer just to Men. If, for example, I say "Elves", I could be referring to all Elves, or to some specific Elves, or to a group or type of Elves. The text as published, then, has the virtue of ambiguity.

Would this fall on this category?
And also for example the use of Men in the fall of Gondolin when it clearly referst to Elves and even Orcs. Does that falls in here too?

b) with implicit indication that JRRT almost certainly would have changed/deleted it. But we must base this on some evidence or text from JRRT or CJRT; that is, a text of greater precedence suggesting beyond reasonable doubt a contradiction with a text of lesser precedence, or

Does the Mechanical dragons fall in this category.

Personal aesthetics are not to be used in establishing the actual events in the narrative; all changes and decisions must be justified by the above principles, either:

Are the aesthetics used in for example the Fall of Gondolin.
There is a great diff in the narrative between the Bolt Fog and the Unfisished Tales Version of Tuor and his Coming to Gondolin.
From what I have been able to read, I think it's outside of the scope of the principles, Right?