AR Write-Off Workflow Issues - When specifying User Entered Definition Criteria on the Approval Proc

What is most preferred is to be able to specifiy User Entered, Definition Criteria that would evaluate the Entry Reason Code for writeoff workflow.

However I have read the following in PS Books and attempting the the second option:

Within PeopleSoft Receivables, you can restrict the users ability to write-off amounts on the payment worksheet, maintenance worksheet, or draft worksheet. There are two methods to restrict write-off amounts:

·         Limit the amount that can be written off. Maximum write-off amounts can be defined for the business unit, bill-to customer, and individual user. If any of these limits are exceeded, the system does not allow the user to save the worksheet.