We sweep Stanford and are ranked behind them. That tracks.
Yeah, if the only data set was that match, I would agree with you that PSU should be ahead of Stanford.
It seems that the biggest issue was where the two teams were ranked the previous week:
Stanford - 4
Penn State - 12
So in this week's poll, Stanford dropped 4 spots to 8, and PSU moved up 3 spots to 9.
Rankings early in the season in WVB are often pretty volatile. A lot of teams are still working on their new lineups, or dealing with injuries. In that context, I try not to read too much into a win (though PSU looked really good in their sweep over Stanford), or to read too much into a loss (though PSU didn't look very good in their 3-1 loss to Kentucky, especially in the 4th set).