Hi Satheesh,
System will capture the cost center along with WBS element if the WBS element has created as a statistical, in that case user has to input CC manually while posting for real object. However, if the WBS element does not create as statistical, in that case system wont capture the CC automatically or default from WBS master data along with WBS. Here if the user has to input the CC manually, in that case system stores it as statistical object.
Regards,
Mukthar