When you are running at half throttle with the pure sine wave transformer, the peak voltage is less than when you're running with a chopped wave transformer. The smoke heater will heat faster and hotter with a chopped wave simply because the heating effect is not linear like it is with a pure sine wave.
This effect disappears with command mode and full throttle on each respective transformer as the output waveform is pretty much the same at that point.
Here's a comparison of the CW-80 at half throttle and full throttle. You'll note that the peak voltage is the same in either case.
Now compare that to the Z4000 waveform at 12V and at 19V settings. Ignore the voltage at the bottom of the screen, it's actually 10 times that reading, probe type was set wrong.
You'll notice at the 12V setting, the peak voltage is around 18 volts, at the 19V setting, the peak voltage is 28 volts.
The fact that the pure sine wave actually varies the peak voltage is why in conventional mode chopped wave transformers tend to generate more smoke. Note that's only for unregulated smoke units, if there's a regulator in the mix, many times the chopped waveform at part throttle will seriously degrade the smoke output.