The System Maint Costs tab shows different information depending on whether you are viewing the actual system itself, or whether you are viewing a level belonging to the system.
If you are viewing the Maint Costs tab for the system, this tab shows all the postings that have occurred against work orders raised for any level of the system. You can see the work order number, when the expenditure was posted, and the amount of expenditure and commitment.
If you are viewing the Maint Costs tab for a level belonging to a system, this tab shows all the postings that have occurred against work orders raised for that level of the system. You can see the work order number, when the expenditure was posted, and the amount of expenditure and commitment.