What a crock of s**t. I checked out when you got through 13 minutes of ISO demos without mentioning pixel density or disclosing the pixel counts of the sensors you used in your demo. Your equation makes ZERO logical sense if it doesn't account for pixel density.
Put it another way -- compare the low light performance of the Sony A7s (12 MP) to the A7r (36 MP). The sensors are the exact same size, but the A7r is MUCH noisier because the photosites are (roughly) 70% smaller.
Similarly, a 4 MP MFT sensor will likely have much better high ISO performance than, say, a 24 MP FF sensor. So that "square of the crop factor" nonsense you invented is pointless.