I'm not sure what's your point? The first "
gap down" of 2097 was from his injury from AFO, a difference of only 1.16 times (showing that he didn't lose that much power from the injury itself).
Then he gradually lose that power over the next years, down to 7500, a difference of 2 times, until he gave up his Quirk to Deku, where he experiences a massive gap down of 4158, confirming us once again that he lose more power after giving up his Quirk than after gaining the injury, and it makes sense, the Quirk is the most important part of his power.
But surprise, the All Might who has lost
more than two-thirds of his "Quirk numbers" and doesn't even have the Quirk anymore.... can actually summon more power before that massive gap down.
Yes that's correct, the All Might who lost even more power compared to Prime AM after the injury and many years can still summon more power after the gap down.
And what I'm trying to say with this? AM from Chapter 1 should be able to summon the same or even more power than his prime by going plus ultra, showing that the difference between his prime and his injured state is not that great (unless you think he can summon 60x times more power than normal by going Plus Ultra, Imao).
Have you ever thought about the possibility of All Might being more durable than the USJ Nomu without the Shock Absorption? Think about it, according to your logic, the USJ Nomu didn't receive any damage at all up until the very last punch that surpassed the limit of his Shock Absorption and
broke the Nomu's face and had his eyes blank (knock out) meaning that this Nomu actually got one-shotted by AM's last punch according to you.
And before you say the High-Ends durability would just scale above the USJ's AP because of taking the recoil of their hits, I remind you that the USJ Nomu's punches only bruised and hurt All Might's skin, while AM's last punch after surpassing the Shock Absorption limit knocked out the Nomu, meaning that someone stronger than the Nomu wouldn't be able to cause the same damage Mirko can to the High-Ends.
What I'm trying to say is, AM's durability>>USJ Nomu's durability without Shock Absorption<High-Ends that fought Mirko.
The fact that AM can still tank the recoil of his Plus Ultra punches confirms his durability is higher than his AP (unless going Plus Ultra increased his durability somehow).
Excuse me? How is going from 15,000 to 7,500 over the years, "almost as bad" as losing two-thirds of your power in an instant (7500>2500)?
It's no discrepancy, the situation simply warranted All Might summoning more power than he did almost a year ago in the story, by going Plus Ultra he can bridge the gap of his weakening, a gap that at no time was said to be immense.
Stop treating every moment in the series as a discrepancy of your multiplier, Imao the only discrepancy is the multiplier itself.
They can be stronger AM normally, but once he goes beyond his limits he can easily surpass them all, plus I still think AM is more durable than any of the High-Ends, after all the statement was only about AM's normal strength, not Plus Ultra AM neither his durability was involved on those statements.
Why would he need to do that? It's already stated his stats surpass the Nomu that... Bruised AM a bit Imao.
One-shotting High-Ends doesn't mean she could one-shot weakened AM. It makes sense how a Prime AM level character could tank her kicks.
The doctor was referring to his prime, plus his statement implies Shigaraki is not that much weaker either.
Endeavor is the only one that confirms Shigaraki is as tough as AM, even though he can one-shot High-Ends left and right, even Endeavor admits AM is more durable than the High-Ends, so once again this confirms Mirko wouldn't be able to one-shot even a weakened AM.
The only meme I see here is this multiplier that goes against logic and most statements in-verse, it's not my fault you are unable to find answers to those questions.
So yep, my answers to yours question is that AM simply being built differently, strength and durability are not the same thing, High-Ends might have a strength on the level of AM, which can bruise himself, but that doesn't mean they are as durable as him, like Shigaraki actually is (this explains why Endeavor's Prominence Burn or Hell Spider can't one-shot or cut apart Shiggy, and why Endeavor can take hits from Shiggy without dying).