Execution plan does not match between explain time and execution time

Some time ago, I have observed that some sqls used bad execution plan during run time, which are different from the execution plan that we obtained by autotrace or explain plan statement. Here is an example (the environment: 9.2.0.8):

The sql is as follows: (changed the table name for hiding confidential information)

select 'Pots,',count(distinct(od.master_order_id))
 from tableOD od,
      tableSD sd
where
      sd.MASTER_ORDER_ID=od.MASTER_ORDER_ID
  and sd.SUB_ORDER_TYPE in (1,3,4)
  and sd.product_category in (2,3,17)
  and sd.SUPP_ORDER_ID=0
  and sd.service_type='Install'
  and od.RECEIVED_DATE between To_Date('05/20/08  00:00:00','MM/DD/YY HH24:MI:SS')
  and To_Date('05/20/08  23:59:59','MM/DD/YY HH24:MI:SS')
  and (sd.SSPUNITY in ('N') or sd.SSPUNITY is null )
  and (sd.DRY_LOOP_IND in ('N') or  sd.DRY_LOOP_IND is null )
  and (sd.HARMONY_DATA_RECEIVED = 'N' or sd.HARMONY_DATA_RECEIVED is null )
group by trunc(od.RECEIVED_DATE),sd.SSPUNITY,sd.HARMONY_DATA_RECEIVED,sd.DRY_LOOP_IND;

The explain plan obtained from explain plan statment is:

-------------------------------------------------------------------------------------------------
 Id   Operation                         Name                     Rows   Bytes  Cost (%CPU)
-------------------------------------------------------------------------------------------------
   0  SELECT STATEMENT                                               2    122     14  (15)
   1   SORT GROUP BY                                                 2    122     14  (15)
*  2    FILTER                                                                         
*  3     TABLE ACCESS BY INDEX ROWID               TABLESD           1     38      5  (20)
   4      NESTED LOOPS                                               2    122     13   (8)
   5       TABLE ACCESS BY INDEX ROWID             TABLEOD           2     46      5  (20)
*  6        INDEX RANGE SCAN           ORD_DTL_RECV_DATE             2             4  (25)
*  7       INDEX RANGE SCAN            SSD_MASTER_ORDER_ID_NUK       1             4  (25)
-------------------------------------------------------------------------------------------------

Predicate Information (identified by operation id):
---------------------------------------------------

2 - filter(TO_DATE('05/20/08   00:00:00','MM/DD/YY HH24:MI:SS')<=TO_DATE('05/20/08                23:59:59','MM/DD/YY HH24:MI:SS'))      3 - filter("TABLESD"."SERVICE_TYPE"='Install' AND               ("TABLESD"."DRY_LOOP_IND"='N' OR "TABLESD"."DRY_LOOP_IND" IS N ULL) AND               ("TABLESD"."HARMONY_DATA_RECEIVED" IS NULL OR               "TABLESD"."HARMONY_DATA_RECEIVED"='N') AND               TO_NUMBER("TABLESD"."SUPP_ORDER_ID")=0 AND               ("TABLESD"."PRODUCT_CATEGORY"=2 OR "TABLESD"."PRODUCT_CATEGORY "=3 OR               "TABLESD"."PRODUCT_CATEGORY"=17) AND ("TABLESD"."SSPUNITY" IS NULL OR               "TABLESD"."SSPUNITY"='N') AND (TO_NUMBER("TABLESD"."SUB_ORDER_TYPE")=1               OR TO_NUMBER("TABLESD"."SUB_ORDER_TYPE")=3 OR               TO_NUMBER("TABLESD"."SUB_ORDER_TYPE")=4))      6 - access("TABLEOD"."RECEIVED_DATE">=TO_DATE('05/20/08   00:00:00','MM/DD/YY
              HH24:MI:SS') AND "TABLEOD"."RECEIVED_DATE"<=TO_DATE('05/20/08               23:59:59','MM/DD/YY HH24:MI:SS'))      7 - access("TABLESD"."MASTER_ORDER_ID"="TABLEOD"."MASTER_ORDER_ID")  33 rows selected.   

However, during execution time, the execution plan obtained from v$sql_plan is:

--------------------------------------------------------------------------------------------
 Id   Operation                        Name                 Rows   Bytes  Cost (%CPU)
--------------------------------------------------------------------------------------------
   0  SELECT STATEMENT                                                            
   1   SORT GROUP BY                                         1042  63562    420K  (6)
   2    FILTER                                                                    
   3     NESTED LOOPS                                        1042  63562    420K  (6)
   4      TABLE ACCESS FULL           TABLESD                1042  39596    416K  (6)
   5      TABLE ACCESS BY INDEX ROWID TABLEOD                   1     23      5  (20)
   6       INDEX RANGE SCAN           TEMP_1                    1             4  (25)
--------------------------------------------------------------------------------------------