Initial call duration will be used to determine the current wait time interval, and play the associated announcement, until the "use previous X calls" parameter is met.
For example, lets say your EWT Table looks like this:
No Wait Time Interval Greeting ID
1 Up To: 00:00:30 1
2 Up To: 00:01:00 2
3 Up To: 00:02:00 3
After all times above 4
if you set the initial call duration to 00:01:00 and you configure the Use Previous X calls to calculate EWT is set for 2, you should be played greeting 2 from the EWT Table (up to 00:01:00) until 2 calls have waited in queue. Once two calls have waited in queue the system will calculate the EWT and play the correct greeting.
Sometimes the context sensitive help is more useful than the documentation too. On any screen in CallPilot Manager you can click the help button to brin up the CS help which will describe the parameters on the page you are viewing. Here is some the CS help for Skillset EWT properties.
14)If you use Expected Wait Time (EWT), enter the number of calls you want to use to calculate EWT in the Use Previous ___ calls to calculate EWT box. This is the number of previous calls that are used to calculate the average call duration of a skillset. The number can range from 2 to 256. The default is 10.
15)If you use Expected Wait Time, leave the EWT Increase Allowed check box selected if you want the system to recalculate the EWT if it increases and continue to play the appropriate EWT greeting. If you clear the check box, callers will not hear recalculated expected wait times if the wait time increases. Whether you select the check box or not, callers will hear the appropriate EWT greeting if the wait time decreases.
16)If you use Expected Wait Time, in the Initial Call Duration box enter in mm:ss format the initial average call duration that is used to compute EWT. The average call duration is updated whenever a call is released from an agent. The default is 00:03:00.
HTH!
-SD-