Procurement type "X": STOs or Production Orders

Hi,

In our organization, in the MRP2 view of material we maintain Procurement type "X" and Special Procurement 40 (Stock transfer from plant B).

We want (in a specific period of time) the MRP run in plant A to generate STOs from plant B, and in a different period to generate production orders in plant A.

I checked the "source list" indicator in the material (Purchasing view) .

I tried to handle the situation through source list: to define which scenario is active, but I couldn't sort it out: the MRP run, always generates Purchase req. for STOs no matter what I maintain in source list.

Any ideas how to control it?

Thanks!