Nope, that does not make sense. If that was the case then adding Sherman's HE to the Easy8 would be a nerf.
It simply would not be a nerf it would be a buff.
Sherman 75mm gives the player the option to use the best AI shell than any medium has, Sherman 76mm has the option to use the very powerful HAVP round AT round.
That is simply not a disadvantage since it allow these units to punch above level.
Finnaly there is even less logic to use the existence of HAVP rounds a reason to buff the AOE of AP rounds as general_gawain has done.
You are misunderstanding the point entirely, and I'm not sure why.
Having to switch between different shells (With the associated delay) before you can use them is clearly a disadvantage. Please answer my question:
Would the Sherman be stronger if it retained both its shell types, but automatically switched (instantly) between them dependent on what would be optimal in a given situation? Yes Or No.
Nobody is saying that the Sherman is underpowered due to this, the shell-switching disadvantage is included as part of the tank's balance, due to it having two exceedingly good shell types. The two strong shell types are an advantage, the fact you have to manually switch between them is a disadvantage.
"Nope, that does not make sense. If that was the case then adding Sherman's HE to the Easy8 would be a nerf. " is a non sequitur and has absolutely nothing to do with the argument. You seem to not quite understand what is meant by "disadvantage", perhaps this is a language-barrier issue.
Example: The Sherman having lower armour than, say, the PIV, is also a disadvantage, even if both tanks are balanced. Relative strength isnt important.