I'm at 140 days, so I'm not exactly in the same position. But I believe we have a similar receipt date (mine was April 6). I called USCIS again today and the agent said they're still "working on cases from April 2nd" but that the last time the chart was updated was August 11. It is apparently updated once a month.

I'm not even sure if that April 2nd date is correct. Sigh... I really wish there was a way to make them more accountable for their actions.