Apparatuses for controlling gas flow are important components for delivering process gases for semiconductor fabrication. In one embodiment, a method of achieving improved transient response in apparatuses for controlling gas flow is disclosed. Specifically, by providing a command to the apparatus to deliver a predetermined mass flow rate at a future turn on time, the apparatus is able to pre-pressurize a P1 volume so that the response time of the apparatus is no longer dependent on the speed of the apparatus's control valves and the limitations of the control loop.