In Classified Renderers, when manually setting the "Break Values", you can set a break greater than the maximum statistic, but you can NOT set a break lower than the minimum. It forces you to the value of the minimum statistic. What if you have data that might go lower than this in the future? What if you just want to set nice clean breaks? I don't see why the smallest break must be greater than or equal to the minimum statistic.
This can be gotten around by loading values from another data set, but this is a lot of extra work to setup that data as needed.