Thanks again for all the replies. What I learned is that United is selling Business Class and First Class upgrades up to the time of the flight and those upgrades become increasingly cheaper as flight time approaches. The potential upgrade sales may delay people coming off the waitlist and in some cases will replace potential upgrades using instruments.

I was able to use 20 PP today, but not in the way I had expected.

Flight 1. 6 hour flight. Ended up 3rd and 4th out on the waitlist.

Flight 2. 3 hour flight. Wife and I same itinerary. Wife clears while we’re in air on first flight. I’m now 1st on the waitlist. 2 First class seats unbooked. 45 minutes prior to boarding, one additional First seat is booked. 15 minutes later the last First seat is booked.

So at this point I realize my wife and I will be in separate cabins. Her former Economy Class seat and the seat next to me is empty 10 minutes prior to boarding and there are 12 - 15 empty seats in Economy overall. But I joke with her that United will seat the proverbial 600 pound man next to me anyway. Sure enough, a huge bodybuilder ended up in her former seat next to me. His right shoulder takes up about one-third of my seat space. I text my wife and let her know she needs to switch. The bodybuilder was happy - taking pictures of himself flying in First to send to his wife. My wife and are reunited in Economy.

I was happy enough. The body builder seemed like a nice guy who doesn’t sit in First much, so a treat for him and so get to burn some fairly worthless Plus Points.