Fix invoice fee editor

config/Windows/editfee.xml

 			var costField = findChildObject(this, 'cost');
 			this.dataSet = function() {
 				descField.text = window.rowData[2];
-				costField.text = window.rowData[4];
+				costField.text = window.rowData[7];
 			};
 			button = findChildObject(this, 'submit');
 			button.clicked.connect(function() {
 				query.prepare("UPDATE invoice_items SET description = :name, cost = :cost WHERE invoice_id = :id AND record_type = 'FEE' AND item_id = NULL AND description = :oldname AND cost = :oldcost");
 				query.bind(":name", descField.text);
 				query.bind(":cost", Number(costField.text));
-				query.bind(":id", Number(window.rowData[1]);
+				query.bind(":id", Number(window.rowData[1]));
 				query.bind(":oldname", window.rowData[2]);
-				query.bind(":oldcost", window.rowData[4]);
+				query.bind(":oldcost", window.rowData[7]);
 				query.exec();
 				query = query.invalidate();
 				window.close();