This video shows how to calculate duration between planned start date and current date time using schedule. https://community.servicenow.com/community?id=community\_article&sys\_id=cf112ad81b152c101e579979b04bcbca Updateset is available here https://developer.servicenow.com/connect.do#!/share/contents/3287388\_fix\_script\_to\_calculate\_difference\_between\_planned\_start\_date\_and\_current\_date\_of\_a\_change\_request?t=PRODUCT\_DETAILS