Usually when people talk about an airliner's range, they talk in terms of nautical mileage. But in reality, the real performance figures from the plane's manufacturer are based on endurance (time) at a given power output/fuel flow.
So, what *IS* the time/endurance of a 757 and A321 at normal cruise, fully loaded, with required reserves? I suspect not more than about 6 to 6 1/2 hrs.
Example: PHL-LAX is 2088 nautical miles. At a somewhat normal groundspeed, Westbound, of 400 kts, that can be achieved in just under 5 1/2 hrs. Add 100 kts to the headwind, as has been the case recently, that's just 300 kts/hr, or just a hair under SEVEN hours. This is why I believe the endurance is in the 6-6 1/2 hr range.
Do the ETOPS 757's have extra tanks to make the longer trips and allow for unusual headwinds? How have the winds been going West to HNL? What's their range (in time), and does it differ from the non-ETOPS?