Aug approvals should kick-in arround middle of Apr, for sure.
Keep in mind that the INS processing speed relies more on the case number for all Immigration Benefits applications rather than the I-485 case only. Althought the number of cases for immigration benefit in Aug hit record high, it was not as scary as you saw in those official polls. The new case receipts was arround 500-600k before March and it jumped to 700-800k from March till August. The encouraging part was that despite the big jump, the VSC maintained a good speed of approving cases. It only took us 3 months to see the first July approval since the first March approval was reported in this forum. The VSC was actually speeding up in the past 3 months, not even mention the holiday season. There was no sign for retrogression at all. We have more than enough reason to believe that first Aug approver will appear in the middle of next month...