LOCK has IGNORED on trigger.

Dear Expert,
I got a trouble with LOCK on my table (Inquery table).
I've put the LOCK (using select bla.bla for update)
on trigger(trigger insert) of Table_A. It's work properly.
when i tried "insert into Table_A bla.bla.bla" with more
than 5 user in same time

Code...fm_In...fm_Out..fm_Balance
---------------------------------
* 009 3 0 3
# 001 10 0 10
* 009 10 0 13
# 001 10 0 20
* 009 15 0 28
# 001 0 3 17
# 001 0 1 16
# 001 0 4 12

But when i put the "Insert into Table_A" command on
the other trigger's table. That's LOCK is ignored.

Somebody help me please...

GOD Bless You All and Bravo Postgre
-----------------------------------
Yudha Setiawan.