two Purchasing UOM

Good day

we have a client that wants to be able to purchase paper both in Reams and in Sheets (they have two suppliers that each have their own preferred UOM)

How do I set up the OUM such that the Purchasing UOM and Secondary UOM are not the same, but both must allow purchase order processing?

This is the current item master setup:

It does allow them to create the Req in Sheets, but the conversion screen does still shows the quantity in Reams