If you want any information to appear in the Ship-To address lines other than the customer address, then a Ship-To code is required. And as you know, Ship-to Address codes are stored in Adagio Invoices in a separate data file that is not importable to (though you can copy them). So you are correct that you'd have to create a 'blank' ship-to code for each customer and set this 'blank' code as the default in the Invoices company profile to get this.