Merchant overtime fee governs customs services outside normal working hours on payment, including services beyond the customs area. Customs levy of merchant overtime fee applies where Customs officers perform functions outside prescribed duty hours, on holidays, or at places beyond the Customs area; it covers examination, loading/unloading, escorting and other Commissioner authorised work, is charged per officer category at prescribed rates, includes minimum and block billing rules, and is payable in advance after Customs assessment before officers are posted.