Legal, But...
Disclaimer: to be clear, I do NOT fly jets in the Airbus/Being class. That said, a lot of this discussion appears to emphasize all engines operating and one engine out (or lost at a critical moment) that pushes performance to the absolute limits of 'legal.' I also appreciate that many, if not most performance parameters include a significant fudge factor.
All considered, virtually all of my training repeatedly emphasized the concept that "Legal is not necessarily smart, safe flying." Again folks, I do not fly these birds and or in their usually tight flight schedules. In my environment, the pilots make the final call. I've never pushed those numbers to the absolute limits and to my knowledge, nor have my colleagues.
Perhaps the original inquiry was only an academic inquiry, yet some of the responses suggest that AB and B pilots routinely push these numbers to the hilt. And perhaps I've missed something. In any case, I won't fly that close to the edge of the performance envelope. If I've missed something, please remind me. Flame if you must and PM is also welcome.