Asking for Clarification About the Delivery Transaction Implementation

[VOID001]

In the delivery transaction, percona sysbench uses "SELECT FOR UPDATE" in

        rs = con:query(([[SELECT no_o_id
                                     FROM new_orders%d 
                                    WHERE no_d_id = %d 
                                      AND no_w_id = %d 
                                      ORDER BY no_o_id ASC LIMIT 1 FOR UPDATE]])
                                   :format(table_num, d_id, w_id))

But from the TPC-C spec I don't find out any place that requires this statement to perform locking read on the record. Could you please give an explanation about it ? Since the performance will be better if we use non locking read