I put a bid in a few weeks back for my flight this Tuesday evening VS155 LHR-LAS for £550 each (two passengers) upgrading from PE to Upper. This bid was shown as "poor" on the dial but hey ho. Had been watching the seats in the last couple of weeks, there were 13 free out of 31 on Saturday night. When I looked at my bid on Saturday evening it showed a countdown timer, this expired at 0335 on Sunday morning, this was exactly 62 hours before the flight.
I woke up on Sunday morning to an email from my CC company telling me there had been a charge on my account and if I wanted to query it I was to get in touch, otherwise all was ok. This email was timed at 0336, just one minute after the auction ended. I got an email from VS around seven hours later telling me i'd been upgraded, I logged in to manage my booking and chose two of the (still 13) empty seats.
Looking at the seatmap now there are only six empty Upper seats and my old seats in PE have been taken by someone else.