Are you running iTest 4.0? (I created it with 4.0 and if you're using 3.4, you might get a warning accordingly, but this doesn't depend on any new features in 4.0.)
I didn't see any repeating nested structures in your samples.
The problem with block mapping for something as complex as this with so many variants is that the block map gets more and more complex to manage as you keep adding in new variants of the response. It is, of course, possible -- and you're almost there. But you'll notice that I built the entire pattern-based response map in only 15 minutes or so, and that's its big advantage.
And one of the best things about pattern maps is that you can use regex's where you need them to do just about anything you need to do. In block mapping, by its nature, we have to be more restrictive, and that leads to the kind of challenges you are seeing.
The thing that many people don't realize about pattern mapping is that a single pattern can span many lines. So you don't have to handle each line separately. And that usually makes it very easy and quick to create.
