The Divinely-inspired Scriptures ARE the final authority....what mere human or human organization has any authority ABOVE them? There certainly are levels of human knowledge and understanding of God's word, but that doesn't change the fact that what God has spoken through the prophets/holy men of God as the Holy Spirit carried them along, by design, is the highest authority and determiner of what is the truth. That is why we must continue to study to show ourselves approved of God able to rightly divide the word of truth and be able to give an answer to everyone that asks us of the hope that is within us with gentleness and respect. Some believers are better equipped to do that than others because they HAVE done the work while others are still learning. Nonetheless, God's word is the authority.
BTW, the argument is between "the Bible in the hands of the individual Christian believer" versus "the Bible as understood by the church whose corporate memory and institutional continuity goes back to the Apostles". Nobody in the discussion is positing an authority superior to the Scriptures, so that's just a red herring.
But that wasn't my point in posting, as I believe I've already explained.