I had to get a new passport this past spring because of a name change. Since my daughter had renewed her passport at the main US Post Office in Hato Rey (across from Plaza Las Americas on Roosevelt Ave.)several months before, I knew that I had to go early to make the list. As you mentioned, they only process a certain number of passports each day from 8 am till 11:30 or 12. I was pretty pleased with myself that I had arrived by 8:15. What I didn't know was that they open the office a couple hours earlier so that people can sign up on the list before 8 am! So, even though I was there at 8:15, I was at the bottom of the list.(At least I made the list.)
I had to wait until a little before 11 am before they called my name. I was quite surprised to see that most of the people there were filling out the forms as they sat and waited. Even when their names were called, they hadn't finished the forms.
The one positive thing was that the man at the counter was so patient and pleasant with everyone. He explained what people needed on their forms, explained what they needed for IDs (some people had to leave and come back with proper IDs), and appeared to be there to help!
Perhaps I've lived here too long. I didn't come away annoyed, but just happy that I had competed my passport renewal.