Don't you hate it when someone starts a thread and never resolves it? Well not here my friends. :)
Our last race of the first half of the season was June 14. But instead of ice or cold air, the AC was blowing only a mediocre cool breeze. We already had an appointment at the dealership after that race so I wasn't too mad. They said they were just going to replace our unit. Well, sure enough, when they tested it today, it was extremely low on freon.
Somewhere, somehow, this sealed unit had a minor leak and that was the source of our problems. I ran the new unit today for almost an hour when we got home. Nice and cool, no ice, or anything.
Thanks to everyone for your suggestions. But I wanted to follow up in case anyone else goes through a similar problem. :)