How to prorate additional costs for several receipts on Sage 300 Purchase Orders Steps: Select the additional cost on the Additional Cost entry table.Click the Cost/Tax button or press F9 to open the Detail Costs/Taxes screen.Click the Dist. Cost button to display the Cost Allocation screen.Highlight the receipt you want, and then click the Distribute Proration column heading.In the Distribute Proration screen that appears, distribute the additional cost and the billing rate (for billable details). Sage 300 Request Support