How does this `LeaveTimeBalance` relate to `edu.wisc.hr.dm.absbal.AbsenceBalance` (generated from [`hrs-portlet-absbal-1.0.xsd`](https://github.com/Jasig/hrs-portlets/blob/cf5659220406211e6c016204d3244d20b43ab644/hrs-portlets-api/src/main/resources/xsd/hrs-portlet-absbal-1.0.xsd) )?