인덱스 강제로 태우기..(너 너무 안탄다..)

분명 인덱스 컬럼순으로 조건절을 태웠는데...
인덱스를 타지 않는다..
인덱스 컬럼순이다..
GJNO1
ACCTKDCD
ACCTDATE
BUSDATE
FINICD
PARTCD
ACCTCD
CHITNO

INDEX 시스템에 맞기기-----------------------------

select acctcd,count(distinct gjno1),to_char(sum(exchamt),'999,999,999,999,990')
  from (
       select acctcd,gjno1,exchamt
         from test
        where gjno1 in(select code2 from test where code1 = 'GJNO1')
          and acctkdcd = '7102'
          and acctdate = to_date('&&yymmdd','yyyymmdd')
          and busdate = to_date('&yymmdd','yyyymmdd')
          and finicd in('1','2')
          and partcd = '3101'
          and acctcd in('551010301','551010303')
          and jukyo = 'TEST'
        )
group by acctcd

PLAN------------------------------------

SELECT STATEMENT     Cost =
  SORT GROUP BY
    MERGE JOIN
      SORT JOIN
        VIEW
          SORT UNIQUE
            REMOTE
      SORT JOIN
        REMOTE
------------------------------------------
Elapsed: 00:14:46.42

INDEX 강제로 태우기-----------------------

select /*+ INDEX_FFS(IMSI_N320) +*/ acctcd,count(distinct gjno1),to_char(sum(exchamt),'999,999,999,999,990')
  from (
       select acctcd,gjno1,exchamt
         from test
        where gjno1 in(select code2 from test where code1 = 'GJNO1')
          and acctkdcd = '7102'
          and acctdate = to_date('&&yymmdd','yyyymmdd')
          and busdate = to_date('&yymmdd','yyyymmdd')
          and finicd in('1','2')
          and partcd = '3101'
          and acctcd in('551010301','551010303')
          and jukyo = 'TEST'
        )
group by acctcd

PLAN------------------------------------
SELECT STATEMENT     Cost = 198
  SORT GROUP BY
    NESTED LOOPS
      VIEW
        SORT UNIQUE
          REMOTE
      REMOTE
------------------------------------------
Elapsed: 00:00:04.07

차이가 나도 너무 난다... 근데 의문인점이... 왜 인덱스를 타지 않을까??
강제로 인덱스를 태워야한다면..
처음부터 명시하라고 하든가.. 왜 옵션처럼 해놓구는..

너무어렵당.. 공부가 필요해 ??? 보내줘~~~ ㅋ