I just wanted to go back and answer my own question regarding parking for Platinum passes. As was mentioned earlier, parking rates have increased, but so had the cutoff times... instead of a 5pm cut off, it was listed as 6pm. But no mention was made on how Platinum passes were going to be dealt with, as they originally had a 5pm cutoff time as well. As I was due to renew my pass anyway, I thought I'd ask a few different team members for clarity, and here's what I was told pretty consistently.
Technically, Platinums can park for free prior to 6pm. However, if you look at the pass itself, or the park website, it still says 5pm. Though one team member thought that the mobile site said 6pm. They are aware that there are inconsistencies in the information, and they are working to clarify it.
We were told the reason the passes (and perhaps the website) will likely continue to say parking is only good until 5pm is to give a buffer. That way, if someone comes in a bit late, say 5:05, they will still get the free parking, and Universal looks generous. That said, the hard cut off is 6pm. If you're in line at the parking booth at 5:55, but it takes 6 minutes to get to the booth itself and it's now 6:01... whammo, you gotta pay $10. The computer system will not allow for the free parking once it's clock changes to 6pm. So this way, when the pass still says 5pm, there's a bit of give.
I can say this exact thing happened to me once at the casual fast food place Pick Up Stix. They had a lunch special that was good until 3pm. We were in line at 2:50, but the orders before us took so long, by the time we got to the front... no more lunch special prices, and the employees couldn't do anything about it.
It's a bit confusing, but I can see why they do it.