About posting invoices with overridden billing amounts

On 11-2 Work Orders/Invoices/Credits under Markups and Overrides, there are two lock checkboxes that you can select. When posting an invoice where either lock checkbox is selected, a ledger transaction is created without using any amounts or accounts from the invoice grid lines or any amounts from the Total Markup. When either checkbox is selected, the posting amounts only come from the Billing Amount text boxes.