No..there are three basic flaws...and both are yours.
Counting.... not your strong point.
So, you think receiving 478 W/m^2 won't get you any warmer than receiving 239 W/m^2?
Where do you think that extra energy goes? Oh, I know! Magnetogravitic fields!
If you have AN OBJECT....a single object radiating at 478wm2....it would radiate at a temperature of 303K...or about 29 degrees....
but according to the SB equation, when you have 2 objects radiating, you don't add them together to get a temperature higher than either...you subtract and get an actual emperature that is somewhere between the two...
On that graphic...they are adding the radiation from the earth...to the radiation supposedly coming down from the atmosphere and claiming that two radiators radiating at -18 degrees can generate a temperature of 29 degrees...48 degrees warmer than either...that...you could prove in a lab...hell you could prove it on your kitchen counter....pour a cup of water at room temperature in a tall glass...then pour a cup of water at 100 degrees into the glass...measure the temperature of the two combined....I positively guarantee you that according to the SB Law, and your thermometer, the resulting temperature will not even be 100 degrees...much less a temperature higher than either..
And yet, you seem to believe that one radiator radiating at -18 degrees and another radiator radiating at -18 degrees can generate a temperature 48 degrees warmer than either...