Okay we'll go with your logic.
Let's say piccolo at 400 busted the moon with a casual attack.
Gohan SSJ2 is atleast at 600,000,000
600,000,000 / 400 = 1,500,000
1,500,000 moons casual attack, my statement still stands, i don't see team 1 tanking a multi planet attack casual.
However, this logic has flaws, the stronger you are the bigger the technique multiplies your powerlevel ( Piccolo from 400 to 1,200 with special beam canon ), Cell's Solar Kamehameha is also a better technique than the ordinary Kamehameha, therefore it multiplies much larger, thus it's not an exaggerate statement saying he can destroy the solar system with a full powered attack ( This can also mean he could destroy the sun, to destroy the solar system altogether ).