If you want to charge the customer from the specific Date of the tasks, that would be the Billable timesheet entries. That means the entries, once transferred to a Bill or Check or Credit Card Charge that pays the vendor, would be Not Billable. Or, you make the timesheet entries Not Billable, and the purchase transaction has the data in lumped entries, and this would be Billable. Don't make them both Billable. If you do not charge that directly to the customer, then Both sources of this data should be Not Billable.