Kepler
Should not the confessions be in agreement with the Gospel? And where one feels the Gospel says something different should not a
sola scriptura Christian defer to scripture?
Take the Westminster Confessions as an example... Westminster conflates the Word of God with the entirety of scripture (
Westminster Confession of Faith I.4) and therefore those who affirm the Westminster Confessions in a quia manner view the Bible to be the inerrant Word of God.
However, scripture never makes this distinction and our Confessions specifically state the the Word of God is Jesus Christ, God's only Son. In essence, a quia manner in regards to Westminster ends up having the Westminster Confessions trump scripture. We don't have that problem with the Book of Concord IRT to the Word of God 'cause Luther knew better
Anyway, I do not believe that the Lutheran confessions (or any confessions for that matter) should ever be held above scripture and therefore a quatenus approach (in so far as) makes much more sense to me...
All in all, I can only think of one issue off the top of my head where ELCA defers to scripture and that is the ordination of women...
ETA: I think that you will find ELCA Lutherans to hold to the Confessions if there are differing opinions on certain passages when it comes to various views of soteriology or God's relationship with man and the world. Take monergism for instance. The Confesssions are monergistic but there are scriptural passages that alude to synergism. Now if a Lutheran were to completely go against the confessions and affirmed synergism because there are some passages that can be read that way then they have taken any and all authority away from the Book of Concord.
In essence, the Confessions are an authority to be viewed along with scripture (IMO) but not something that should be considered equal to scripture and not something that must be affirmed in it's totality to still be considered authoritative.