Technological feat aside:

Revolutionary heat dissipating coating effectively reduces temperatures by more than 10%

78.5C -> 70C = (78.5 - 70) / 78.5 = 0.1082 = 10% right?!

Well, not really. Celsius is an arbitrary temperature scale. The same values on Kelvin would be:

351.65K -> 343.15K = (351.65 - 343.15) / 351.65 = 0.0241 = 2% (???)

So that’s why you shouldn’t do % on temp changes. A more entertaining version: https://www.youtube.com/watch?v=vhkYcO1VxOk&t=374s