the third book

[engwaalphiel]

There is nothing wrong with their passage.
It makes great sense that after Frodo's journey and the permanent scars he has that he leaves at the grey-havens.
As well as it making great sense it is such a tearful ending.
Think about it , when pippin and merry turn up to say goodbye when frodo almost gave him the slip again and the last line spoken by Samafter returning home (one of the most powerful lines in the book and a well known quote)

I'm back

i think i'll leave it with that.