Billable vs non-billable transaction controls

 My client has defined a task-level transaction control to make certain ODC expenditure types non-billable.   All other transactions incurred against this chargeable task are billable.   The billable flag is checked at the task level.  

On the transaction control, the Limit to Transaction Controls check box IS NOT checked.   Expenditure Category and Expenditure Type fields are populated with the expenditure catgory / expenditure type combinations that should not be billable.  Chargeable check boxes are checked.   Billable LOV is set to 'No' on the transaction control.   The effective start date of the transaction control is set to the start date of the task.    From the Oracle Project Guides I have read, the expenditures loaded against this task should be marked as billable except for the transactions incurred against the expenditure types that are listed in the transaction controls as non-billable.