If you check this field, you are able to enter a default account for miscellaneous purchases from this supplier. When the invoices for this supplier are being final coded, this purchase account will be coded by default in the final coding window. Invoices are registered in the Register Supplier Invoice procedure.
This purchase account is only loaded when you are final coding invoices that are not linked to a purchase order (such as invoices for telephone charges, rent, electricity etc.). The invoices that are linked to purchase orders will get their final coding information from the purchase order instead.
If you have configured a standard account for Purchase account for additional order rows in the Chart of Accounts / Standard Accounts procedure in the Global Settings module, you can enter an exception account for it here.