Is this an actual thing on VS Wiki? If so, where does it come from? No battleboard I've been on has such a rule and I can't recall anything supporting that given how many feats there are that say otherwise.
This only makes sense for Quincy due to Blut working for Offense and Defense with the same function, but the Shinigami, Hollows and Fullbringers don't have such a thing. Their durability is just their durability and their offense is based on their capabilities.
It shouldn't be, we wouldn't assume that people have Durability equal to AP unless we had proof. Characters like Visored Ichigo and Resurreccion Grimmjow having AP = Durability makes sense since they were trading continuous blows with each other, but you can't be saying that everyone has AP = Durability because they have one Durability or AP feat that you scale to the other stat.
There's enough evidence of it as well, Zaraki's statement doesn't even fully support that notion.
Apparently not, that reasoning is being used in the recent Cero Oscuras calc and I recall it being used in previous threads as well against me when proposing revisions. It's also applied on some profiles, I see it on Ikkaku's profile already.