Ibn Ezra, R.Tov Elem and "Who Wrote The Bible?"

This regarding the contention that the (well-known-in-the-blogosphere) hints of post-Mosaic prophetic pieces to the text constitute adding or taking from Torah [my emphasis];

"One can ask, doesn’t the Torah write of itself “Do not add to it” (Devarim 13:1)? The answer is that which R’ Abraham (Ibn Ezra) himself wrote in his commentary to Va-etchanan (Devarim 5:5) that the words are like bodies and their meanings like souls; therefore, there are many sections of the Torah which are repeated two or three times, where each adds something that the others don’t, yet are not considered ‘additions’ to the Torah. Furthermore, in his first comment in Lech-Lecha (Bereishis 12:4) he states that ‘do not add to it’ was only said with regard to the commandments, meaning, that when the Torah warned us not to add, it only warned not to add to the number of mitzvoth or to their fundamentals, but not about adding words. Thus, if a prophet added a word or words to explain something about which he had a tradition, this is not considered an ‘addition’".

From ADDerabbi here . Also end notes to the chapter "Chate'u Yisrael" from David Weiss Halivni's "Peshat and Derash", and section on the 8th Ikkur from Shapiro's "Limits of Orthodoxy Theology". Also in his review of Shapiro's book, R. Y. Blau makes some valuable comments on Ibn Ezra and R. Tove Elem;

I would also add that all of the verses mentioned by Ibn Ezra are relatively peripheral to the biblical story, such as an aside alluding to where Og’s crib can be found. By incorporating such limitations on post-Mosiac verses, it would seem possible to allow for a few isolated verses as coming from a later prophet while still asserting that for all intents and purposes,the Torah of ours can be traced back to Moshe. It may be that we should reject Ibn Ezra’s view as a maverick position outside the consensus. Even if we do accept it as a legitimate possibility, the fact that we cannot give a concrete number of verses that can be attributed to a later author without sliding into heresy in no way invalidates the idea that a boundary exists. All concepts include gray areas but those questionable areas do not undermine the concepts. (p.184)

Interestingly, he does not mention the statement that these post-Mosaic contributions come "to explain something" about which there was a tradition. Maybe it didn't even need to be mentioned. Is there the possibility of later additions being made to clarify context and meaning, based in Nevuah - but not on a specific narrative mesorah?