I hooked up an oscilloscope to check out the various dimming levels (and FWIW, it’s forward phase):
Brightness 1/100, power on for about 1.520 ms out of 8.333 ms, or 18% of the time, 8% of the sine wave’s area
Brightness 50/100, power on for about 4.880 ms out of 8.333 ms, or 59% of the time, 64% of the sine wave’s area
Brightness 100/100, power on for about 7.360 ms out of 8.333 ms, or 88% of the time, 96% of the sine wave’s area
