Regarding the voltage settings in windows - they definitely stay what they were set even after a reboot. I've manually set the voltage to 1.1V (nothing about the voltage in the .bat launch file), the PC froze and I had to reboot. After the reboot the voltage is still at 1.1V. I think this is worth looking into, because I've no clue what my default voltage is supposed to be, or whether it would return to normal lower voltage when it's idle.
This is most certainly not intentional and I cannot do anything about it since cgminer consciously changes settings back to default, but windows decides that cgminer should crash every time instead.