Freight getting seggregated at item level

Hi..

.I created PO for 2 line items:

Item A Qty=10 price =50 INR

Item B Qty=20 price = 60 INR

Freight at header Level= 300 INR

Total value of PO= 2000 INR...

Now when i am saving it...it is distributing freight amount among 2 line items i.e.

Item A: freight= 88.24 Inr

item B : freight=211.76 INR....Total freight =300 INR..

While GRN also it is taking 2 times freight account...i do not want to seggregate it at item level..

Utsav