Thanks so much for posting your experience. May I ask for more info? How long ago did you buy UCT tickets? Before a price increase? Did they bridge to the current gate value? Did the CM automatically give you the right price or did you have to say or ask "the magic words - bridging"?
Thanks again for posting!!! It's so good to hear a positive experience as this is stressing me out!
Sure

I bought the UCT tickets in early February, so just before the price increase.
When I bought them, there was a 65$ per ticket savings. The price increase added another 40$ savings or so. Yes they bridged to the current gate price.
- Purchased UCT tix: 6-day with PH, WPF&M no expiration tickets. These tix had the best savings at the time (65$). Paid 544$ each with Mousesavers link.
- Gate value before the price increase: 607$
- Gate value after the price increase: 650$
- Upgraded to 9-day PH, WPF&M, NE. Gate price: 772$
- Difference of 122$. This is exactly what I was charged.
I'm not sure that "bridging" is the magic word...I don't think the CM's know exactly what that means. In other words, I think the computer tells them what the ticket is worth, and that depends on whether the ticket has been used or not.
My CM was quite confident when she told me it didn't matter if the ticket had been used yet. Then we discovered that one of the 4 tickets hadn't been used to enter a park (a different CM at a park guest relations window didn't prioritize the tickets properly, so I ended up using the 'wrong' ticket to enter the park that day). This obviously affected the value of that ticket, and it was different than the other 3.
So she had to fix that first, then do the upgrades. First she quoted 143$, and I said that wasn't right. Then she said 130$, nope still not right. Then she said 122$ - Bingo! We joked around that I wanted to keep going to see how low she'd go. She explained that she had missed a button that she needed to click.
The upgrade part was pretty quick, maybe 10 minutes. The fixing of the other CM's mistake took an hour!
In the end, they gave each of us 3 extra FP+ for our troubles, so now I have 6 for today (my last day). I wasn't planning on going to a park, but it's kind of hard to pass up....