Clarify "Expand to the level present in the deep insert request"

In 11.4.2.2 Create Related Entities When Creating an Entity, we state that:

"If the service responds with 201 Created, the response MUST be expanded to at least the level that was present in the deep-insert request."

However, we don't specify what information must be included in that nested response (i.e., do unaffected properties need to be retrieved?) nor whether the entire response must be expanded to the maximum level, or if different elements may be expanded to different levels, based on their depth within the request."

We are finding scenarios where it is hard/expensive to return more data that specified in the request. Since we have since added the ability to specify select/expand on the results of the request, we are fine paying the extra cost to re-query whatever data is required, but doing this by default in order to return a 201 Created seems onerous.

Note that, in 11.4.3 Update an Entity, we specify:
"Upon successful completion the service responds with either 200 OK and a representation of the updated entity, or 204 No Content"

We do not here specify which properties of the representation must be returned (i.e., only the updated properties or all of the properties or some default set of properties or???)