I really do not see any value in having these two things be separate items. And I think could be easily combined in to one message group. If you wanted to get just the short answer and not the collection information in your discovery request, then I think we could add a field to the discovery request that is a boolean for extended_data: yes/no. But even then, I do not really see that as being of value.
The current work flow is:
Client Sends Discovery Request ->
<- Server Sends Discovery Response
Client then needs to send Collection Information Request ->
<- Server then Sends Collection Information Response
The extra back and forth is needed right now just so someone can do a Poll. I think it is an extra amount of work that is really not of value. People can still withhold sending the information if they choose.