fixed amount

dear,

i have 2 condition type, ZZZ1, ZZZ2 item level, manually input (no access sequence), cond class = A, calculation type = fixed price (B)

i made sales order for 100 PCS, with ZZZ1 = 100 USD, and ZZZ2 = 100USD

then i do delivery order n good issue for 80PCS

then i bill for 80 PCS, but the value of condition type ZZZ1 and ZZZ2 changed to 80 USD. i want the cond type ZZZ1, ZZZ2 will be same even the quantity in outbound delivery is different with SO.

how we do that? please input.

Thanks,

Best Regard,

Hendry