I don't believe ever that the CIS will stop to process the I-485 cases. I also believe that some cases will be approved fast and some cases will be approved slow since there is no way to have all the centers and all the officers process the I-485s in the same pace. As lawyer Fan described in his memo, some ealier applicants took more than one I-485 petitions. Once these cases are approved or denied, these quots will be released for the other. The CIS will use these quots for the new I-485 cases. There have been some cases got approved before the PD was current. I believe also that the CIS will do this way as they did before.
Your sincerely comments on my understanding are wellcome.