Mileage Schedule Set up in iExpense

We have requirement of below combination of Threshold Distance.

0-8500

8501-20000

0-20000

How this can be achieved in iExpense. As i am able create the Schedules but when i am assigning these details to Expesne Item in Expense Report Template it throws error.

'APP-SQLAP-97352: A different mileage rate schedule that uses the cumulative distance thresholds rule is already in use for this operating unit. You can only use one threshold-based schedule per operating unit.' is thrown by system when same policy is used for defining multiple expense items.

It allows me to create expense item of all above range but when i try to create another Expense Item with either of 0-8500 or 8501-20000 it throws error.