Planned Consumption & Unplanned Consumption
(1) How does SAP recognise the difference between "planned consumption" and "Unplanned consumption". Is planned consumption what is issued from stock based on a prior reservation (and what you have already seen on the MRP list before it is issued.) ?
And what does SAP consider Unplanned consumption. Can safety stock calculation be done on either of these?
(2) If returns are happening for a material does the consumption value go down for such a material ?
Which set of consumption values (if at all) gets posted during the material movement is defined in the customizing of movement types (OMJJ). For some it's always the total consumption, for some it's always the unplanned one and for some it is dependent on whether the issues was done with reference to a reservation (then it's a planned consumption).
The way these consumption values are taken into account in MRP is defined in the customizing of MRP types (don't remember the trs). Look for a set of indicators talking about "Forecast".
In the standard:
1) For reorder point planning (VM) the total consumption is used to calculate the safety stock and the reorder point.
2) For forecast based planning (VV) the total consumption is used to build the forecast which will be used to compile the order proposals.
3) For deterministic MRP (PD) the unplanned consumption is used to calculate the forecast which in turn is added to the actual demand.