freight entry in invoice

Dear Friends,

I have an issue like this..

PO is created with 10 items and freight charges are entered in header level.

GRN is done for 3 items..

While making invoice for partial delivery, system is not taking freight condition.

"Checking invoice with goods/service+planned delivery costs".

Can anybody tell me what could be the possible reasons...

Points will be awarded immediately...

Raju