Low cost query takes more time to execute

 We are running a query as follows: 

   SELECT t.transaction_id,

          t.data_feed_code,

          t.instance_code,

          t.site_id,

          t.transaction_date,

          UPPER (t.supplier_code) local_supplier_code,

          UPPER (sa.supplier_name) local_supplier_name,

          UPPER (

             SUBSTR (t.local_commodity_code,

                     1,

                     INSTR (t.local_commodity_code, '~') - 1))

             local_commodity_code,

          UPPER (scc.local_commodity_desc) local_commodity_name,

          UPPER (cat_util_param.field_trim (t.description))

             invoice_description,

          UPPER (s.site_name) cost_centre_name,

          UPPER (cat_util_param.field_trim (t.purchase_order_description))

             purchase_order_description,

          UPPER (cat_util_param.field_trim (t.purchase_order_line_item_desc))