I think that it can be difficult to compare the juice consumption between different people.
That being said, I think that it is pretty correct to say that wattage consumes juice. I'm running the OCC ni head on my new subtank plus (its got the improved airflow base and v2 rba, still would like to compare it to the STM sometime), and running temp control so I'll be interested to see how that changes my juice consumption as the coil will heat then use far less wattage.
I still feel that the OCC half ohm coils are more efficient than a dripper.