EAD, AP and I-140, I-485

Anybody know the procedures for processing of EAD, AP,I-10,I-485. I saw that the processing time in San Diego disctrict office is only 1 day, 21-30days for San jose district, I am totally confused by this processing.
I guess that our cases will be recieved by service center, then transfer to different offices, then approval processing, is that right? if it is, what's the meaning of processing time posted in 4 different service center?
I got a message from the following website, seeing the much shorter processing time for EAD, AP, I-485 than those provided by 4 service centers.

your comments will be warmly welcome.