OSP WIP job quantity changes

 Hi,

We have done all the required set ups to enable the OSP functionality. The requisition creation time has been set "At Job/schedule release".

So once we release a WIP job this creates the requisitions for the entire WIP job quantity. However later on once the requisitions are created if we make the changes in the WIP job quantity 

system allows us to increase or decrease the WIP job quantities but this change in the quantity is not getting reflected in the purchase requisition. 

Is there any set up that we are missing in WIP or in Purchasing to acknowledge the changes in the WIP job quantities.