Ability to Add Prior Years After Application was Created

Summary:

I thought we are not able to add prior years after application was created with a specific start year but Admin Guide suggests that we can do it. When did it change?

Content (please ensure you mask any confidential information):

I thought we are not able to add prior years after application was created with a specific start year. When did it change? For example, if start year is FY17 and later we need to add FY16 and FY15. Any issues with that?

Planning Admin Guide "You can add years to the beginning or end of the calendar, but you can't reduce the number of calendar years without creating a database."