Stop watchlist queries using default branch/plant

I have come across some unexpected behaviour with Watchlists.  We are trying to set up advanced queries across multiple branch/plants and add them to a watchlist.  The end-user has default branch/plant set up in P400951 to auto-populate the branch field on transaction screens.

I understand from this document [E1: 43: Business Unit Defaults from P400951 Instead of Advanced Query (Doc ID 1900453.1)] that Advanced Queries are designed to build on top of filter field values when an application is open.  In this situation the end-user needs to delete the default branch field before selecting the advanced query within an application.