optimum ?
Unless otherwise defined, presume maximum weight for the conditions.
If your ops eng group has an operational background and is in cahoots with the CP and the two aren't too beholden to the bean counters .. a bit of fat might just be injected into the data.
For instance, when QF started out with reduced thrust takeoffs (a LONG time ago), the then Ops Eng boss, Wal Stack, mandated (as I recall) 1000ft ASD pad as a flight crew sweetener.