one purchase organization with multiple calculation schema for a single vendor

Purchasing Organization- P          Purchasing Product -Z                       from Vendor- V

For product -Z Calculation Schema C (Contain MRP)

Purchasing Organization- P          Purchasing Product –Z1                       from Vendor- V1

For product –Z1 Calculation Schema C1 (Contain MRP & DISCOUNT)

So while making Purchase order  by Purchasing organization P it will trigger separate calculation schema for separate product for separate vendor.

Is it OK?

Then

If a Certain purchasing organization purchase two different Product (with two different calculation schema)from same  vendor then how the calculation schema will be triggered