Outbound ORD-HND booked ANA business and applied PP to get on the waitlist. 24 hours before the flight the upgrade canceled out with F2 available (and flight left with 2 F seats empty).

Return flight a week later same story - F3 available at 24 hours and the waitlist cancels. 3 F seats went out empty.

Not worth going out of my way to book NH and deal with converting UA flight numbers etc when the only way to get confirmed is the flight being F4 (at least) or more at 24 hours before departure.