Multiple ASCP plans for supply and ATP

We are considering running 2 ASCP plans…one with a heavy forecast to drive the actual supply chain…one with little to no forecast (just sales order demand)  for ATP. The reason for this is planning has never quite wrapped their arms around how ATP analysis considers the  forecast first and then supply. We want to use real supply to make decisions on if material is available for customer orders. We forecast at the configured model level. If this is still making any sense to you…is there a way to have ATP analysis ignore ASCP recommendations? Think about it…a purchase order might