There are a large number of rate overrides and possible configurations within Boostlingo. Rate overrides can exist at multiple levels, but they follow a specific order.
Overrides created on an invoice will always take the highest precedence. This is the rate hierarchy following invoices:
Invoice-level rate overrides.
Appointment-level rate overrides.
Interpreter rate overrides.
Zone rate overrides.
Account-level rate overrides.
System-level rate defaults.