Consumption Based MRP

Hi,

We are running consumption based MRP using MRP Type as VB. We run consumption based MRP daily. In this, when ever there is change in stock level due to consumption, the system reschedules the old schedules also. We don't want to disturb the old schedules generated by MRP as we confirm the vendors as a Firm Schedule.

Can you please guide me on how i can run consumption based MRP daily and not tamper old schedules.

Regards

Shankar