I don't think the impedance effects the flow rate. I have however checked a few other sites re the flow rate of these injectors and they are showing same rate for 0 280 155 003 and 0 280 150 811 both at 264 cc/min. On the same tables they show the 968 injectors at 296cc/min.
See
WitchHunter Performance - Injector Cleaning & Flow Testing Services
Interesting ...