I am flying from SEA to LHR with VS106 on 14th (Thursday). I want to try my luck on upgrade from economy to next class, either PE or UC. It is less than 48 hours away so bidding is closed and I was anyway not intend to try that. Will try calling their support or will ask at desk. But before that I want to get idea, how many seats are still vacant in these classes.
I am trying to see that on expertflyer and it looks like all PE are booked already ?

Though UC looks like some are available

If UC are still available till Thursday morning, will they let these seats go in cheaper than usual fare? What are your thoughts ?
PS : I booked economy classic with points.

Regards