Unfortunately, another cron question

OK... I've searched the forums and found MANY messages about cron. Unfortunately, I must be dense today because I'm not sure what to do for my needs.

Like others, I have a couple RSS feeds setup to be shown on my site. In the "administer->aggregator->edit feed" page for a specific feed, I have set the update interval to 1 hour. After the hour came and went, the "administer->aggregator" page3 shows that the feed's last update was 2 min 27 sec ago. However, it shows the next update as having 0 sec left. Does this mean the feed will not be updated in another hour? If so, what do I have to do to make sure it IS updated?

Any help is greatly appreciated.

Rick