BPMN2 — Unclear/contradictory handling of visualized Data Inputs/Outputs

The spec does not provide much clarification on how the Data Inputs/Outputs notation is used.

As an example, consider a process that is calling another process. The called process has Data Inputs and Data Outputs.

If I create a data association from the calling process to the Call Activity, clearly the target of that data association would be a data input of the called process.
And yet the spec states that:

• DataInputs MUST NOT have incoming DataAssociations.
  So, there's a contradiction here. DataAssociations do and should target DataInputs.

Or, is that statement intended to describe visualization of the DataAssociation (i.e. the DataAssociation visually stops at the CallActivity boundary and does not visually connect to the Data Input, even if it is actually connected in the semantic model)?

If the latter, why not allow the Data Association to connect to the Data Inputs? Doing so would result in a more explicit visualization of the underlying semantics. If I had multiple Data Inputs, I would be able to tell at a glance which Data Input is being targetted by which Data Association.

1. Pdf pg 221, section titled "Data Inputs". Replace entire second paragraph (including sub-bullets) with the following:
[See word doc for formatted version: 10_process-data_updatedFor317.doc]
The Data Input is an item-aware element. Data Inputs may be visualized in a Process diagram to show the inputs to the top-level Process or to show the inputs of a
called Process (i.e. one that is referenced by a Call Activity, where the Call Activity has been expanded to show the called Process within the context of a calling
Process).

• Visualized DataInputs have the same notation as DataObjects, except MUST contain a small, unfilled block arrow (see Figure 10.55).
• DataInputs MAY have incoming DataAssociations.
• If the Data Input is directly contained by the top-level Process, it MUST NOT be the target of Data Associations within the underlying model. Only Data
  Inputs that are contained by Activities or Events may be the target of Data Associations in the model.
• If the Process is being called from a Call Activity, the Data Associations that target the data inputs of the Call Activity in the underlying model may be
  visualized such that they connect to the corresponding data inputs of the called Process, visually crossing the Call Activity boundary. But note that this is visualization
  only. In the underlying model, the Data Associations target the data inputs of the Call Activity and not the data inputs of the called Process.
  2. Pdf pg 223, section titled "Data Outputs". Replace entire second paragraph (including sub-bullets) with the following:
  [See word doc for formatted version: 10_process-data_updatedFor317.doc]
  The DataOutput is an item-aware element. DataOutput elements may be visualized in a Process diagram to show the outputs of the top-level Process, or to show the
  outputs of a called Process (i.e. one that is referenced by a Call Activity, where the Call Activity has been expanded to show the called Process within the context of a
  calling Process)..
• Visualized DataOutputs have the same notation as DataObjects, except MUST contain a small, filled block arrow (see Figure 10.57).
• DataOutputs MAY have outgoing DataAssociations.
• If the Data Output is directly contained by the top-level Process, it MUST NOT be the source of Data Associations within the underlying model. Only Data
  Outputs that are contained by Activities or Events may be the source of Data Associations in the model.
• If the Process is being called from a Call Activity, the Data Associations that originate from the data outputs of the Call Activity in the underlying model may
  be visualized such that they connect from the corresponding data outputs of the called Process, visually crossing the Call Activity boundary. But note that this is
  visualization only. In the underlying model, the Data Associations originate from the data outputs of the Call Activity and not the data outputs of the called Process
  Disposition: Resolved