To take this a step further with regards to the Queue Summary and Detail report (as well as the iWrkgrpQueueStats DB views), it depends on how you have your callbacks setup. More than likely, it is one of 2 different scenarios:
Scenario01:Calls morph into a callback.
In this scenario, a call will enter Queue01, wait for a predetermined amount of time, and chooses to leave a callback (more than likely via an in-queue menu). When the caller elects to leave a callback, the call morphs into a callback while still in the queue.
What you'll see in the report for this scenario (if you choose to group/summarize by media type) is 1 Entered for a call media type, and 1 Answered for a callback media type.
Scenario02:Call flows out, callback replaces the call, callback is placed back into the queue
In this scenario, a call will enter Queue01, wait for a predetermined amount of time, and chooses to leave a callback (more than likely via an in-queue menu).
When the caller elects to leave a callback though, the call will actually flow out of the queue (typically back to an IVR node), is replaced by a callback interaction, and the callback interaction is then placed onto the queue.
What you'll see in the report for this scenario (if you choose to group/summarize by media type) is 1 Entered and 1 Flow Out for the call media type, and 1 Entered and 1 Answered for a callback media type.
Also something to note is that there is no report out of the box that will directly related the inbound call, the inbound callback, and the outbound call by the agent back to the caller. That will require custom logging to tie together those interactions, then a custom report to display that relationship.
I hope this helps.
Thanks,
Trent.