Special Production Order

Hello Guru,

Yesterday we have issued, we want to have a production order that we dont want to direct posting of cost during Production Order declaration. we created a dummy material with mat type is non valuated, we made a production order with this kind of material,and doing the PO via CO01 SAP ask me to maintain settlement Rule: Overview, where i indicate the category and the cost center, after that release and confirm it log working hour for labor, and with this we made settlement via KO88. after all this process i done and check the PO that we made there is cost in analysis and its balance? is this because we indicated in the confirmation that activity in labor has values that's why the were register cost in my production order?

how could we achieve that our order will not be posted directly a cost?any set-up eitheir with the material,cost center etc?

thanks