Purchase requisition over demand creation

Hi

The process is following:

1. Create forecast for purchases products

2. Run MRP

3. Purchased requisitions are created

The question. Is it imaginable to specify determination that Purchase requisitions are created with quantity 20% much than demand?

For example. Monthly request = 100 PC. I would similar to accidental that I request 20% more. So aft MRP, Purchase requisition is created with Qty = 120 PC?