I have installed Rotating Tweets version 1.6.11 and the configuration has the default 2 minutes for getting the latest tweets from Twitter.
However, the rotating display is never updated without the page getting refreshed. I posted a new tweet but it didn't show up for close to 10 minutes and I refreshed the page and saw it included.
I suspect that a consequence of this problem is that the time indication of the tweets being shown stays the same number of minutes as time goes by.
You can see the behavior at http://venkat-raman.com/