There should be a button that unallocates all payments at once. It is really time consuming having to go through accounts who have made a large number of payments and unallocate each one individually just to make edits to the fees and discounts. In addition to this, you can't make changes to the fees and discounts if the first billing month has already past. So you have to change the payment plan, then unallocate the payments, then adjust the fees, then reallocate payments across the plan so that the monthly installments are balanced. That is way to much manual effort for a web system that should make those efforts simple.