Fiori My Travel and Expenses (V2) + BAdI TRIP_WEB_CUSTOMIZING: Removing Expense Types not working

Hello,

I would similar to restrict Expense Types disposable in Fiori My Travel and Expenses (V2) by implementing BAdI TRIP_WEB_CUSTOMIZING, but this is not working.

Requirement is that usage of definite disbursal types is constricted to users with peculiar role. 

In my method IF_EX_TRIP_WEB_CUSTOMIZING~USER_EXIT_CUSTOMIZING I tin delete disbursal types successful tables EXPENSE_TYPES and EXPENSE_TYPE_PROVIDERS, but these are inactive disposable successful Fiori App dropdown list. Using outer breakpoint I tin spot that method is called by App.

Any ideas wherefore this is not working? 
Thanks,
Frank