Actual Cost Update

Hi...

We're in BPCS ver 6.1.01 client server.
i want to ask about actual cost update for this case,

Started from 1 january '02 i've bought an inventory - INV-X1
the transaction for this inventory :
Transaction     Quantity/cost unit              Freight charge          Total 
Amount
buy 1           100 unit @ $ 800                $ 1.000         $ 81.000
buy 2           200 unit @ $ 110                $    990                $ 22.990
buy 3           100 unit @ $ 125                $ 1.100         $ 13.600

i use transaction efect that acumulate the total amount as the actual cost
for that item.
then actual cost for that item in last position is $ 293.975/unit.

but unfortunately there is a return for the freight charge on the
transaction of buy 2 toal amount for that transaction should be 22.500 only.
can we recalculate atomatically for that case in BPCS...???
the actual cost for that item now is 292.75.
how can we change the total amount for that item on transaction buy 2 ?
and how about the recalculation for the actual cost ?


Regards,
Yanti