The pulse width modulation is strategy to achieve the desired voltage, but doesnt have too much impact on the drain current unless you want to get into the more advanced details like peak current vs average current.
The basic principles are quite simple; energy cannot be created or destroyed, only transformed. -Law of Conservation of Energy
What that means to us is that the input power (watts) from the battery must be equal to the output power that is consumed by the coil. That is a very simplified version, I go into more detail here:
Calculating Battery Drain Current
In the end, if you vape at 10 watts, then the battery must supply 10 watts of power (plus efficiency losses) regardless of resistance. In an ideal circuit (no efficiency loss), if battery voltage is 4.0V then the battery drain current will be 2.5A @ 10W, regardless of resistance.
Again, this is all pretty simplified and only talking about the average current.