If Mario was amped by 120 Stars he would have iced Bowser in one punch, even if he is amped, it's not by much, certainly not to the extent proposed in the calc. And no you can't say "Well maybe he did one-shot Bowser and the fight is just for gameplay", if you make this argument you are stretching the foundation of what is canon to the point where the things that happen in game can just not be what happens, which is somewhat okay in some instances, but the developers had a clear intent of how the fight plays out, so to assume it does otherwise would be ignoring the game in favor of headcanon.