This is a pet peeve of mine because I can't emphasize enough how variable the experience is depending on how lucky you are on a given day. We've gone twice since Covid--once in August and once October. Both times, we had a
mix with some waits substantially under the posted time, some waits substantially over the posted time, but
most of the time, the waits were pretty close to accurate (within 5/10 minutes of the estimate in either direction).
It has not been our experience at all that wait times were consistently, across the board, lower than the posted time. I think that was true when they first opened the park in July, but I think it has become a bit of an "urban legend" on disboards as a result of that initial set of reports. Just like the urban legend that there have been no outbreaks of Covid among CMs.
I expect part of the reason for the elevated times today is it is a day after a holiday weekend and some people are taking off an extra day to finish off their vacation. That said, we waited an hour or more for most attractions in October, so it could just be this is the new normal, and last week's shorter wait times were a temporary post-holiday dip that wont last.
Another theory I have is to make up for a potential cleaning stoppage while you're in line. No one's complaining if they get in a 30 minute line and wait only 15 minutes, but everyone would complain about getting in a 15 minute line and having to wait 30 minutes, then complain about the cleaning procedures.
We actually had exactly this happen several times that we got in a line with a posted 10/15 minute wait and ended up waiting 45-60 minutes because of cleaning cycles. They do revise the posted wait after they announce the start the cleaning cycle, but did not increase the wait time before we entered the line in anticipation of the cleaning cycle.