Thanks Jurgen,
I was just providing as much info as possible. The complete issue is this:-
1) One person creates the materials and maintains the valuation class in accounting view as domestic.
2) Another person creates the PRs from the project builder (CJ20N) and claims all the data form the master is auto populated.
3) A third person creates the PO with 14 line items, referencing the PRs. He also claims he cannot make any changes to the valuation type in the ME21N transaction.
4) All but one items get the Import valuation type, one gets the domestic.
5) The goods have been received and the error was noticed while processing payment and Accounting.
So is this human error or a system issue? Please help.