The domain model (2.9.3.2) says that choices is of type PropertyChoiceType and has an optional index, but in the schemas the type is called cmisChoice and has no index.
Furthermore, there's no mention in the schema that hierarchical nesting of choices if possible, whereas it's mentioned in the domain model.

The index is not needed anyway as the choices can simply be returned as an ordered list.
The hierarchical nesting looks to me as a bit overkill to be specified in 1.0 but I'm open to being convinced otherwise.