This article seems to answer some questions:
- There is no direct evidence that it was addressed to Akhenaten, just that it is contemporaneous with the letters found at Amarna and of the standard of royal correspondence. It is probably part of the local copy of letters sent to Akhenaten.
- The dating seems to be on stylistic grounds
- I have wondered why it couldn't be a letter to the king of another country and I am still not entirely convinced that Akhenaten was the recipient. He clearly may have been but it seems to be supposition rather than fact.