OPM Costing in 11.10.5

 I found that using PMAC costing method - in Oracle Process Manufacturing Financials - update the transactions with the last calculated item cost ...

This result in having ALL period transactions posted in the final calculated item cost in this period not cost at transaction time...

and this differs with the discrete ordinary logic that says that transactions should be posted to GL in the transaction time cost not the final period cost ...

So how do you see this problem and how i can solve it ??