For external supplier registration TaxPayer ID required only for Spend Authorized registration

Summary:

For external supplier registration, the client is required to get Tax Payer ID only for Spend Authorized supplier registration however in the Configure Supplier Registration and Profile Change Request page we have a field as Require Supplier Identifier for External Supplier Request which is common for both Prospective and Spend Authorized Supplier. So is there any possibility we can make that not required for the Prospective Registration page? This is required as the Client is using Prospective Supplier Registration only for Sourcing purposes so Tax Payer is not required at that time.