I just got back from doing LAX to SFO to FRA and back. All flights were booked pre-switch over on PMUA .bomb.

LAX to SFO and SFO to FRA were to different PNRs for a variety of reasons.

LAX to SFO UDU worked just fine and I was upgraded both directions about 90 hours out.

SFO to FRA and back was a bit of a mess.
Out I was on a U fare and return on an M fare.

At 24h15m I got told, via e-mail, that I was off the wait list but would be on the stand by list both directions.

SFO to FRA I couldn't check in online because of "doc issues". At check-in I was put on the stand by list and ended up being #5.

At SFO, they told us all to board. As we waited, the GA came on and upgraded folks 1 to 3.

I was sitting next to Mr. #3 who was a 1K on a B fare.
Ms. #4 was sitting in front of me!
Kind of funny because Mr. #1 was sitting in front of her!

Don't know Mr. #1's status but Ms. #3 was also a 1K. Of note is that all of them were in middle seats (and I had been earlier when I booked). Ms. #4 and I both stayed in coach for the flight. :-(

FRA to SFO I checked in just after the window opened. However, I did not show up on the iPhone upgrade list. I called the 1K desk and they could do nothing.

They told me they couldn't even see the list (even had a supervisor look).

When I got FRA, the counter agent was from LH and had worked the PMCO flights so he knew the system. However, he had to get a supervisor to get me "on the list".

That said, once they added me I showed up on the list as #1. I stayed that way until boarding and got my upgrade at that time (#2 and #3 got upgrades too, but that was it).

So it seems at this point, as long as you're on the list before the 24 hours, you shouldn't worry even if you don't show up right away on the airport list 24 hours out.

However, making sure you have extra time at check-in is a good idea for a bit longer so things can get fixed at check-in.