You're thinking along the right lines, imo. Mirror image. Subversion. The same mass ritual means one thing for the naive nice people in the churches with the right side up cross, and the opposite for the elites in the church with the upside down "St. Peter's" cross. It's like Kubrick's joke in A Clockwork Orange where Alex tells the chaplain in prison that the Bible is his favorite book, which pleases the chaplain, but it's secretly because Alex likes reading about Jesus being tortured.