No one can figure out in advance what will happen in an arbitration--which is the point, after all. If you insist in knowing in advance what's going to happen when you protest a bank's action, don't protest a bank's action. Simple.
This is a pretty good article about the process, although it's talking more about credit card debt disputes than MFS:
https://www.creditinfocenter.com/leg...itration.shtml
Note this:
Difference Between JAMS and AAA
Both JAMS and AAA are arbitration services. JAMS (Judicial Arbitration and Mediation Services) is preferable to AAA (American Arbitration Association), as JAMS is most costly to creditors (i.e., increasing the chances they will drop further action). So if you have a choice, elect arbitration via JAMS.