The Must Support and Missing Data page says "Sending Systems are defined as: 1) Ordering Provider Systems and 2) Intermediary Systems when sending to a Rendering Provider Systems using the PAO IG" but could the Rendering Provider System also be considered a Sending System when providing an order response or update as indicated in the flow diagrams? Should the definition be made more generic to reflect the Sending System that the system initiating a RESTful interaction or message?

The definition of "Receiving System" may need a similar update as the Ordering Provider System may receive the order update response.