Errata exists for this version of the document.

All DataVariables used to expose complex data structures of complex DataVariables have the BaseDataVariableType as type definition if they are not complex by themselves. The reason for this approach is that the complex DataVariables already define the semantic of the containing DataVariables and this semantic is not used in another context. It is not expected that they are subtyped, because they should reflect the data structure of the DataType of the complex DataVariable.