BASE_Entity is mantained just like any other dimension in the CoreBUILD > Dimension screen. If you are required to report both Level 1 and Level 2 for a form, rather than duplicate all the source data we idenitify the level 2 differences via tagging and add them to level 1 to report the total for Level 2. A similar tagging approach is done for the Domestic entity where this is the same as Level 1. This is handled via the BASE_APRA_Entity dimension