msn.com shows the AH pps and volume, delayed 20 minutes. When I noticed the real-time quote was down, I checked the msn.com AH report, which showed 20 minutes earlier. At that point, the pps was still well above the closing price, and the volume was 418,000+.
As of 20 minutes ago, the volume AH was 536,000. So that's at least 0.418 million up, followed by at most 0.118 down.
I don't see how 0.118 million shares is meaningful compared to an average regular day volume of 14 million.