Make sure in Manage Job Defaults “Don’t adjust Job Costs when editing Job Invoices” is ticked
Set the setting of the first and subsequent progress claims to Fixed $ Amount
Select Authorise None
Invoice the progress Claim
When you are ready to do final Invoice change settings to Actuals and Authorise All
Invoice Now the Invoice and add to invoice a misc stock code with a description of Less Progress Claim and a quantity of -1 and the value previously invoiced. This will not show on the Job Details Report.