AX2009 offered this feature where you could use the field as a calculator entering the including GST amount shown on the Tax Invoice into the unit price or total field and divide by 1.1 giving you the excluding GST amount which is required (Australia). Since changing to D365 we are finding it difficult as some Tax Invoices only show amounts including the GST so we have to use a calculator to work out the excluding amounts for each line to key into the fields creating more work to process an invoice.