For an unregulated mod, this is correct, but for a regulated device like the Provari, it is not necessarily true.
The voltage and current on the atomizer side of a regulated device is not the same as the voltage and current on the battery side of the circuitry. The wattage however, is roughly the same: The number of watts drained from the battery equals the number of watts delivered to the coil, minus the number of watts lost in conversion.
In short, the main factor determining battery drain with these devices, is the wattage you vape at.
Battery life is also affected by the efficiency of the voltage regulator circuit. The efficiency varies between different device models, atomizer ohms, user set voltages, and battery levels. With that many variables, it is difficult to say anything general about this efficiency, but if I should guesstimate, I'd probably say somewhere between 80 and 98%, give or take, ymmv, etc.
Update: I googled "provari efficiency", and found a
FAQ on Provape.com where they claim an efficiency of 90-95%.