Create Accounting - Cost Management take a long time

Dear all,
to generate COGS, i run several concurrent below :

1. Record Order Management Transactions
2. Collect Revenue Recognition Information
3. Generate COGS Recognition Events
4. Create Accounting - Cost Management

for concurrent 1-3 is completed normal with normal time, but when i run concurrent no. 4 it takes more than one hour to completed. it happened just recently.
how to trace what make it take a long time to complete?

note:
i run all that concurrent daily

Regards,

Suryadi