Interestingly, ANAs LAX and SFO flights use B77W in both directions.
Both ANA and SIA switched to using B77W regularly in early June.
CPA started using B77W regularly from mid-May.
UAE have been using B77W regularly since mid-March.
All airlines mentioned above were using B773 or B777 before the point of their transition to using B77W.
It almost appears as though something changed (?) that now permits them to regularly file plans as B77W.