Production mode is required
BigML has been always using confidences (a pessimistic approach) to measure the certainty of a given prediction. Now you can decide to also see probabilities for model predictions. The fundamental difference between both measures is that probabilities don't penalize a lower number of instances in a given node so heavily.
You can see how the three different model visualizations change by playing with the buttons to show confidences or probabilities at the top of the model view.