You're right, though I'm not sure Angband is relevant.
First off, NoME 1.VI A was revised into 1.VI B. Tolkien repeats the statement of how many years Men had existed before they entered Beleriand, but amends it from 64,534 years to 57,190 years. He still keeps the "not scientifically long enough" statement, too! So the Awakening of Men date should certainly be revised to match that.
But then he did reconsider. 1.XIII.2, for example, places the death of the Trees 96 VY after the Awakening of the Elves, explicitly 13,824 years. Men would obviously have to be younger than that!
But I think it's valid to record what he was thinking
at the time. Ultimately there is no One True Answer to this question, so showing all the options is my preferred aproach.
~
Though of course, we can put them in chronological order.
- The Lost Road - pre 1937. Submitted to Allen and Unwin that year.
- Astronomy - 1937-1949. During writing of LotR.
- PoME TV - 1949-50. Dated by CT.
- Letter 211 - October 1958. Dated.
- NoME 1.VI - 1960. Tolkien dated text A to this year.
So "16,000 years" is the final comment Tolkien made on how long ago the Elder Days were, for whatever that's worth.
hS