change in MRP planning control parameters.

Hi gurus,

i have an issue regarding the control parameters for MRP.

Presently while planning run i am getting some purchase requisitions and some planned orders for externally procured items with create purchase requisition =2( pur req in opening period) with opening period =0.

Hence, we want all the materials( externally procured) to be getting the purchase requisitions without any planned orders at all as the MRP controller can reduce the time converting the planned orders into purcase requisitions.

Can we go for the change in control parameter for create purchase req =1(purchase requisitions).

Please let me know if it has any side effects ????

Thank you in advance.

Naveen.A