I would try checking with a test disk, not sure if sspears new BD test disk has audio tests, if it does I'm sure it's done right.
Also as was told to me using the DVE test disk it was not in an error that the bass was -10db as that is how it should be measured so it may depend on what it's supposed to read.
How does it sound to your ear?
Sounds fine to me. I think I read that the Sony S550 should have all the speaker distances set the same and all levels to zero. I'm sure it was in this forum but I could be mistaken.
Cheers
Mike