The batteries that are used with the magic flight are not designed to hold a large charge, they will run out rapidly, no doubt due to the internal workings of the flight box. If i want a thicker hit i alter my inhale rate and increase the amount of bud in the trench. I've not found it to be a tool for getting super mashed though, just for wandering around out and about getting nice and buzzy.
It may also have been designed to certain specifications, making it "hotter" might simply results in failure of the device or burning of the weed.