Setting the Bill Through Date 
                                                    The firm bill through date controls the WIP that appears on the billing grid. On the invoice, the bill through date also acts as the AR statement cutoff, AR aging, and default invoice date. See Setting Billing Options for the Firm  for more information on setting up the bill through date for your firm.  The grid includes all WIP up to and including the bill through date. 
                                                    You can override the  bill through date for an invoice if necessary if you have rights.  How do I set up permissions?
Open a security group that includes the staff you want to restrict. See Managing Security Groups  for more information. Click Assigned Staff  in the navigation pane and verify that the staff you want to assign rights to are assigned to the group. Click Functional Rights  in the navigation pane. Select the Practice  tab. Expand Billing , and next to the line Override firm bill through date, select Grant . Click Save .  
                                                    To override the bill through date  for this invoice, do the following:
                                                    
                                                         Open the Billing Decisions window .Open Dashboard , click Application Links  on the navigation panel, and then click Bill WIP  under Billing & Invoicing. Select the Clients , Client Billing Groups , or Projects  tab.  Locate the record you want in the grid and select Actions > Bill . Note : You can use search or filters to help you locate the records you need. To use search, enter a client’s or client billing group's name or ID in the Search and bill  box. Click the client name if you see it, or press Enter . See Using the Billing & Invoicing Filters  for information about filters.
  
                                                        Update the date in the Override bill through date  field. 
                                                        Click Save  to apply the new date.