It was as you said.
When I first heard it, I was almost certain that it is grammatically wrong. But when I searched Google, I realized it is used frequently (at least according to the book section).
"As you said" is a dependent clause that needs an independent clause, for "as" in that case is used as a subordinating conjunction. I just do not understand how that subordinating conjunction can be used WITHIN an independent clause. Also, I think that "as you said" is working as a predicative adjective phrase (though it is a clause) and this doesn't make any sense to me.
Is the usage wrong, or am I wrong? And if I am, why?
Well, subordinating conjunction CAN BE used in an independent clause. However, that's only when the subordinate clause introduced by a subordinating conjunction is a noun clause.
Ex: The reason is that I was sick yesterday.
You cannot say the reason is because I was sick yesterday. "Because I was sick yesterday" is not a noun clause.