PO senario

Dear sir,

I have this scenario I make po using p4311 and I received the cardex p4111 show as the following:

QTY 5, unit cost=2000 , extended cost =10000

then I add another line for the same PO with negative QTY and I change unit cost as the following:

QTY -5 , and unit cost 1000 now the cardex show as the following:

QTY -5 , extended cost -5000 and and another line QTY =0, and extended cost=-5000(as zero balance adjustment generated by the system)

now if I post all the these batches will not tally with GL balances and will be adifference between cardex and GL so what is the solution?