John Heywood wrote a book that has equations for this exact discussion in it.

At some point during the intake cycle you will be @ choked flow of the port, at which point the downstream pressure in the cylinder and exhaust pressure doesn't matter. Even prior to choked flow the airflow will increase with boost. Flow will increase as the boost is increased.

If you reduce the orifice size (turbine housing OR intake port) the flow will go down, but for a given restriction the flow will be increasing if you increase boost.