Laura,
It is normal that MRP will consider an STO as a receipt element; this is basic planning. It is unclear to me why you think you do not want it to do so, but I will assume you have some logical reason.
Contrary to what some others may have suggested, changing the scope of check for availability checking has no effect on which elements are considered for MRP. MRP is a completely separate functionality from Availability Check.
For Location > Location STOs (within a plant), then, you normally have the receipt element of the STO in the destination storage location, and the requirements element of an equal amount in the source storage location. Net of these two elements is zero, unless you have already issued the STO at the source location.
Changing the Account assignment from "E" means that the STO will not be relevant for your Sales order (in other words, when you receive this STO into the destination storage location, it cannot be used for your sales order). In a general MTO scenario, it also means that the proceeds of this STO (the stock you received) cannot be used for ANY sales orders.
One way that some people make an STO 'not relevant' for MRP is to alter the destination storage location such that it is not relevant for MRP. You can change the MRP relevancy of the storage location in MM02 > MRP4 tab
Best Regards,
DB49
