Invoice Field Validation Method
This validation method enables you specify how invoice amounts are calculated and how tax amounts are validated. You can also manually enter field values to test if your configured calculations work as expected.
For example, you configure a project for both German and United Kingdom invoices. Since each country has a different discount and VAT tax rates, you also configure a validation method that ensures both country calculations flag invalid results for validation. However, you cannot mix countries that use VAT with those that do not.
Once added, you can configure an Invoice Validation method using the Invoice Validation Properties window.