VaranAwesomenow
Mega Sage
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