FAIL! Open up any calculator, and enter 120x1.2. I GUARANTEE you will get 144, NOT 240.
First of all, it has a power of 100, not 120. And anyway, you forgot to factor in that Judgment (that's how it's spelt, only 1 e) always gets STAB. So, it's actually 100x1.2x1.5=180. Not quite as powerful as you thought.