Query returninng different result

Question

When I run this query:
create or replace
PROCEDURE PROC IS
BEGIN
insert into TEMP
*(aaa,bbb,ccc)*
*(SELECT aaa,bbb,ccc,instanceid*
FROM a, b
WHERE some conditions
and to_char(ddd,'DD-MON-YY') = (select to_char(sysdate-2)  from dual))
and a.instanceid not in (select TEMP.instanceid from TEMP  ));
commit;
END PROC;
I get 477 records
but when I run
(SELECT aaa,bbb,ccc,instanceid*
FROM a, b
WHERE some conditions
and to_char(ddd,'DD-MON-YY') = (select to_char(sysdate-2)  from dual))
and a.instanceid not in (select TEMP.instanceid from TEMP  ))
I get 489 records.
How can this happen, the two querie are different?
What I am trying to do is to have a procedure that is run every 10 min and inserts into table temp all records that have not been added since the last call of the procedure during same day.

Answer 1

first query to be run
select count() from a, b where((((a.a1 = 'P') or (a.a2 is not NULL))*
and a.a4 = 'EX'
and ((a.a3 = '3111')
or (a.a3 = '3311')
or (a.a3 = '3312')
or (a.a3 = '315')
or (a.a3 = '3131'))
OR
*(a.a1 = 'P'*
and a.a4 = 'IM'
and ((a.a5 = '3111')
or (a.a5 = '3311')
or (a.a5 = '3312')
or (a.a5 = '315')
or (a.a5 = '3131'))
*)) and ( a.instanceid = b.instanceid*
and to_char(date,'DD-MON-YY') = (select to_char(sysdate-2)  from dual)
and a.instanceid not in (select TEMP.instanceid from TEMP  ));
second query is the procedure
create or replace
PROCEDURE PROC IS
BEGIN
insert into TEMP
*(SELECT **
from a, b where((((a.a1 = 'P') or (a.a2 is not NULL))
and a.a4 = 'EX'
and ((a.a3 = '3111')
or (a.a3 = '3311')
or (a.a3 = '3312')
or (a.a3 = '315')
or (a.a3 = '3131'))
OR
*(a.a1 = 'P'*
and a.a4 = 'IM'
and ((a.a5 = '3111')
or (a.a5 = '3311')
or (a.a5 = '3312')
or (a.a5 = '315')
or (a.a5 = '3131'))
*)) and ( a.instanceid = b.instanceid*
and to_char(date,'DD-MON-YY') = (select to_char(sysdate-2)  from dual)
and a.instanceid not in (select TEMP.instanceid from TEMP  ));
commit;