Hi,
yes, it's correct. The Service Level timer is started when the call enters the CSQ.
There's a number of resources discussing various aspects of call center metrics, but the key is: the time the customer spends listening to the IVR menu and choosing what to do is the customer's time, this cannot be influenced by the call center configuration. What can be influenced is the time the customer spends in the queue (starting from the moment the customer makes up his/her mind and chooses an IVR option to the point the agent picks up the phone, or the customer hangs up).
This is the reason why the Service Level calculation takes only the number of seconds spent in the queue.
Check out the Historical Reporting Guide for your UCCX version for more details about the other columns.
G.