Trying to Connect Miller's Hierarchies

I have been having a bit of trouble trying to decipher Miller's notions on "Hierarchical theories of meaning," at least to some point where I feel that I have a decent grasp on where she is connecting them(159). The first hierarchy that she discusses calls for a mix of of substance and form as being essential to understanding symbolic meaning. She says that substance "constitutes the aspects of common experience that are being symbolized," presumably through language, and form acts as "the ways in which substance is symbolized(159)." If substance is the idea, then form is the media in which that idea is symbolized, which I suppose may not necessarily need to be words. Miller then throws in a third hierarchical level of understanding when she adds the concept of "context" to the mix, explaining that context is needed because it "specifies the criteria for interpreting both the meaningfulness and property of any communicative event (160)." Context, in one way or another, sets the stage for the language that is being communicated, and with that sense of a setting, there can be a better understanding of what meaning is being understood. With this hierarchy of substance, form, and context in mind, I seem to be having a bit of difficulty being completely certain with how it links with the hierarchy that Miller creates later in her text.
Miller's later proposed hierarchy finally puts the term "genre" into the hierarchical mix, but I am really not sure how necessary it is. In a lot of ways, Miller's definition of genre seems a lot like what is described as context. She notes that "genres are provided interpretive context by form-of-life patterns and are constituted by intermediate forms or strategies (161)", and also says that, "genre is interpretable by means of rules (163)." Isn't all of this what is meant by context? The form-of-life patterns that provide guidelines for interpretation and meaning is really what context was referring to in the first hierarchy that was introduced, wasn't it? Again, I may be way off base and probably overgeneralizing, but it seems like all that Miller's proposed hierarchy does is make her first hierarchy that she talks about unnecessarily complicated, and it is when language is over complicated that it most often fails. I think that in this case, the simpler the hierarchy, the easier it is to comprehend, but maybe someone else can let me in on a little more insight before I take this to the bank.