I think the claim regarding to the Heliocentric solar system is a good illustration the Archbishop's (from my mouth to God's ear) point.
The Pope never claimed that he was "infallibly" proclaiming that the Sun went around the earth. Though that
was the Church's teaching, the Church never said, "We proclaim this because we are infallible." The action was reversed, finally, under the papacy of John Paul II.
Up to John Paul I, however, supposedly all popes from the 7th Century did take an oath not to undo anything their predecessors had done as part of coronation ceremony.
http://en.wikipedia.org/wiki/The_Papal_OathJohn Paul I declined and not "crowned," and either was John Paul II or H. H. Benedict XVI.