I haven't seen this question or missed it in this long thread: Spouse and I are on a paid PlusPoints eligible ticket (single PNR) with PlusPoints requested (Polaris or PP option) round-trip MCI-EWR-ATH, MUC-IAD-MCI. On our last trip to STT, we split as I saw seats in PZ come and go even though #1 and 2; I then called when I saw 1 seat in PZ. So one confirmed and the other waitlisted. and were ultimately both upgraded, so that was great. I've been watching for PZ and RN and haven't seen anything. We are #4 and 5 for upgrade as we were last month. So do we split to get a seat confirmed as soon as it opens up (assuming it is 1 at a time)? Almost all my travel is domestic, so I am a PlusPoints neophyte internationally.

Concerns: Per UA 1K chat -
Agent: I can go ahead and work in dividing the reservation and put the other passenger on a different confirmation number. But as a reminder, once divided, I can no longer merge it in the future. In case the upgrade using PlusPoints was not confirmed, as a Premier 1K member, you will still be rolled over to the Complimentary Premier Upgrade. But your travel companion will no longer be eligible for Complimentary Premier Upgrade because the reservation is divided and she'll be on a different confirmation number.
Me: On our flight last week I got a notification at check in to split my reservation, did so, and my wife was still upgraded with me [FYI UAX YX].
Agent: During check in if there's only one available seat for upgrade, it will prompt you to confirm but the reservation will be split or not confirm and wait until your companion also gets upgraded. However if we divide the reservation prior to check in, the system will no longer detect it since the Complimentary Upgrade request shows up during 24 hours before flight departure.
- is the last agent's statement splitting correct that pre-checkin splits lose companion's CPU chances?

What are your thoughts and guidance if correct?
I haven't split for now given the above - given if we don't get upgraded by PlusPoints (which is looking more doubtful by the day), I suspect our best/only chance would be due to misconnects, so I think I need to keep that option, as it sounds like post check in splits keep companion on the CPU list. I would like at least one to upgrade (I would switch so Spouse is up front at least). There are currently 13P and 4 PP seats showing on the map, down from 21/8 last month. We're #1 and 2 on the return from MUC (772, ~25% more P/PP than 78X to ATH and many more open seats) so no worries there. Maybe ATH will upgauge to 772. Also I thought I read somewhere in Program enhancements, there was to be a double PlusPoints to confirm but that hasn't been offered, and I did not see it at upgrade request (unless I missed it).