also I figured out why some of the classes that we marked as 'full' aren't full anymore. The

manage stock

option in woocommerce was set to true, and value at 0 left in the class. But that was at the max # we had in the class. So when ppl cancelled, that number would increase and allow people back into the class. I did not think that would happen, so now we know and I manually set those classes to "out of stock" . Please let me know if there are any others I should update.