A quick thought:
Even though I would defend multiple levels of meaning of scripture, I want to be careful. There is a strong insight in the argument that there is only one sense in scripture. The basic truth behind this insight is that Scripture cannot mean something that is contradictory to its plain or literal sense. Even though we can discern different levels of meaning this does not mean that meaning of scripture is not one. Scripture has one unified message and that is the salvation we all find in Christ.