SQL - Need to find duplicate records but EXCLUDE reversed transactions

1/1/08    ; 14    ;    70.00    ; N
1/1/08    ; 14    ;    70.00    ; N
1/1/08    ; -14   ;    -70.00   ; Y
2/1/08    ; 17    ;    89.00    ; N
2/15/08   ; 18    ;    95.00    ; N
2/15/08   ; 18    ;    95.00    ; N
3/1/08    ; 11    ;    54.00    ; N
3/1/08    ; -11   ;    -54.00   ; Y
3/1/08    ; 11    ;    54.00    ; N
3/1/08    ; 11    ;    54.00    ; N
3/1/08    ; 11    ;    54.00    ; N

2/15/08    ; 18    ;    95.00    ; 2
3/1/08     ; 11    ;    54.00    ; 3

select dt, abs(qty), abs(val),
       sum(case when reversal='Y' then -1 else 1 end) as count
from transactions
group by dt, abs(qty), abs(val)
having sum(case when reversal='Y' then -1 else 1 end) > 1;

create table transactions
( dt date
, qty number
, val number
, reversal varchar2(1)
);

insert into transactions values (to_date('1/1/08','mm/dd/yy')    , 14    ,    70.00    , 'N');
insert into transactions values (to_date('1/1/08','mm/dd/yy')    , 14    ,    70.00    , 'N');
insert into transactions values (to_date('1/1/08','mm/dd/yy')    , -14   ,    -70.00   , 'Y');
insert into transactions values (to_date('2/1/08','mm/dd/yy')    , 17    ,    89.00    , 'N');
insert into transactions values (to_date('2/15/08','mm/dd/yy')   , 18    ,    95.00    , 'N');
insert into transactions values (to_date('2/15/08','mm/dd/yy')   , 18    ,    95.00    , 'N');
insert into transactions values (to_date('3/1/08','mm/dd/yy')    , 11    ,    54.00    , 'N');
insert into transactions values (to_date('3/1/08','mm/dd/yy')    , -11   ,    -54.00   , 'Y');
insert into transactions values (to_date('3/1/08','mm/dd/yy')    , 11    ,    54.00    , 'N');
insert into transactions values (to_date('3/1/08','mm/dd/yy')    , 11    ,    54.00    , 'N');
insert into transactions values (to_date('3/1/08','mm/dd/yy')    , 11    ,    54.00    , 'N');

SQL> select dt, abs(qty), abs(val),
  2         sum(case when reversal='Y' then -1 else 1 end) as count
  3  from transactions
  4  group by dt, abs(qty), abs(val)
  5  having sum(case when reversal='Y' then -1 else 1 end) > 1;

DT            ABS(QTY)   ABS(VAL)      COUNT
----------- ---------- ---------- ----------
15-FEB-2008         18         95          2
01-MAR-2008         11         54          3