WI - FirstDayOfSchool and LastDayOfSchool data collection

There is a need in WI to collect the firstdayofschool and lastdayofschool. 

What other states have done?

NE has extended the calendar entity to capture this information per calendar.  The information is rolled up to school and to district level.  AZ has extended the calendar entity too.  SC is inclining towards extending the Session and SC informed that the begin and end date per term will not be the accurate representation of the firstdayofschool/lastdayofschool as some academic recovery programs start earlier than the actual term begin date.  Is there a possibility for Ed-Fi to provide guidance on whether to use calendar or session to collect this information?