Performance Tuning :: Cursor Sharing Setting In OLTP Environment?

In an OLTP environment what cursor_sharing setting is preferred?Though typically we retain the original setting for most of the parameters except memory settings etc. I have queries in the following context

No. I am not facing any issue as of now (I am not supporting any Live environment) But I want to know the desgn considerations

First of all in OLTP environment (say one I am referring) we use pl/sql variables which are obviously bind variables Only in case where plan is expected to change we use hard coded values like 'CREDIT' or 'DEBIT' etc. for acc_type column

Again there can be 2 scenario
1) we use the same query for both acc_type values
2) we use 2 different queries
IF v_parameter = 'CR'
select * from accounts where acc_type='CREDIT'...
else
select * from accounts where acc_type='DEBIT'...
end if;

Again suppose the values are skewed and we gather stats with histograms hereIs't it the setting 'cursor_sharing=similar' which will be useful in above case?as with this setting optimizer will 'think' which plan to pick depending upon the values and bind variable peeking is taken care in option 2 above with IF ELSE clause?

BTW
I have carried several tests but not getting conclusive results For example I created following table with skewed data, created index and gather stats with histogram

SQL> select object_id,count(*) from skewed_data_tab group by object_id;

OBJECT_ID COUNT(*)
---------- ----------
5 30
6 2970
7 10797
8 150000
9 300000

SQL> create index i_skewed_tab_data on skewed_data_tab(object_id);

SQL> exec dbms_stats.gather_table_stats(user,'SKEWED_DATA_TAB',cascade=>true,
method_opt=>'for all columns size 254');

Then traced with following options
1) alter session set events '10046 trace name context forever, level 12';

SQL> begin
for i_outer in(select n from ids order by tstamp)
loop
for i_inner in (select /* for exact */ object_id,object_name,object_type
from skewed_data_tab where object_id=i_outer.n)

[code]...

2) set termout off
alter session set events '10046 trace name context forever, level 12';
@/u04/scripts/exact.sql 5
cat /u04/scripts/exact.sql
select /* for exact */ object_id,object_name,object_type from skewed_data_tab where object_id=&1;

But not getting consistent results