A new fee type "Write Off" is needed to allow applying fees to written off accounts. The fee should be available only for accounts in Written Off State.
In terms of Accounting - the fee should be recognised as Income and should allow selecting Any GL account (like currently), except amortisation options.
At account level, add fee details to a new Write Off Recovery section on Account Overview. The schedule should not be impacted by any fees applied after write off.
Once an account is written off, the due amount is normally forwarded to a collections agency that handles the due recovery further on. In some situations, a fee can be charged on the account, either immediately after write off, or during the collections process. Currently Mambu does not support applying fees to written off accounts, however this is needed to support above scenarios.