And its also possible for an interpretation to be the wrong one, even if someone is a good writer.
Again, to use Lorenzo Semple Jr as an example:
In addition to the Batman TV show, the man wrote the screenplays for Papillon, The Drowning Pool , the Parallax View and Three Days of the Condor. Any one of those movies alone would seem to qualify him as a "great writer."
But does that mean he "understood" Batman?
For that matter he wrote the widely-reviled 70s "King Kong" remake. Since he's a "great writer," do we have to assume he "understood" King Kong?
Of course not.