It's 12 mg nicotine per 1 ml, not per 1 drop. But you're correct that 1 ml equals about 20 drops--depending on the size of the drop.
But it still should not cause dizziness. Most vapers tolerate 12 mg very well at medium wattages, 4-6 watts, for example.
But their biggest is 1.2 besides their site gives explanations based on nic level of a cigarette.
I am confused when everyone uses per mg basis they use 1.2. What should 1.2 stand for 1/10th of exact strenght? why?