My child is using a LOT more time than the limits I set

The first explanation is that TimesUpKidz failed to start and enforce limits. Open TimesUpKidz, click the name of the child, and then view the history chart that shows when and for how long they used the computer. If the chart is msising a lot of usage (e.g. you know they were on for 3 hours but only see 1 hour), then contact customer support

Otherwise your child figured out how to bypass the limits. Read how to lock down the computer