If you are using UseEmailReceipts, an email is sent to the user as a receipt when fines are written off or paid. 

There is a difference in how the emails sent that should be fixed:

* When you pay/write off a single fine, an email is sent for that line.
* When you pay/write off multiple using "selected", one email is sent with all information about the selected lines. (nice and expected)
* When you pay/write off all a single email is sent for each line. (unexpected, not nice)

If multiple lines are paid or written off, this should always generate a single email about the transaction.