Many, many thanks for the responses. I've been slow in responding due to some unforeseen chaos (isn't that always true?), but a couple of comments......
I realize I'm being imprecise with my language here. Please forgive me -- this is all sort of new to me. My daughter's "therapy" is probably misnamed -- it's not therapy, it's the Wired for Reading program that I think is often used with dyslexic kids.
The only reason I think we have some hope here is that her reading challenges are caused by the phonological delay, which my insurance company recognizes as a developmental delay. Interventions of all sorts to address developmental delays are covered by my insurance (which i realize is quite generous), hence my attempts to get insurance to cover it. The company self-insures, so realistically, they can cover anything they choose to cover -- which is the only reason why i'm pushing. It will take an appeals process, but I can't get the appeals process started until I get denied -- hence my desire to find the billing code. They won't process (and deny) the claim until I have that information. Of course they won't give it to me.
I'll keep looking....if anyone knows, much appreciate the help. And many thanks for the comments/guidance above -- it's helpful to hear others' experiences.