Encoding/Decoding Discussion Question

In the article, Hall says, "The codes of encoding and decoding may not be perfectly symmetrical...the degrees of 'understanding' and 'misunderstanding' in the communicative exchange-depnd on the degrees of symmetry/asymmetry (relations of equivalence) established between the positions of the 'personifications', encoder-producer and decoder-receiver." I am a little confused to what this means, is he saying that the audience/decoder may have trouble understanding the message since they don't have the same background/knowledge as the producer/encoder? And is it possible for the audience to have perfect understanding of the encoder's message?