I think serial numbers should be added to the purchase receive page as well and become mandatory on that page and should be optional on bills.

At the moment serial numbers are mandatory on the bills page. I think this is a mistake since most manufacturers will send a bill without any serial number and will either send the bill numbers later with the shipping documents or some do not even send the serial numbers by documents you will simply just "view" the serial numbers when you receive the items.

This causes problems because you have to add the bill to the purchase order BUT you cannot do so because you do not have the serial number.

Is is possible the above to be solved easily?