Retroactive Component - What does Default Component do?

Summary:

When adding a retroactive component to an element, there is a field called "Default Component" which is Yes/No value. What does this do?

Content (please ensure you mask any confidential information):

When adding retro to an existing element, you add a retroactive component to it. One of the fields is "Default Component" which is a Yes/No value. Seeded elements with retro enabled set this to "No", but the Oracle documentation says to set this to "Yes". What does this field do, and why are the docs telling us to set it it differently to the seeded element templates? It seems to work either way but want to understand this…