The "FOEX Form - Update Success" is when a DML operation has been successfully performed which is why it is for the region.
I need to understand your requirement since your question is not really clear. Do you mean you want to know when an item's value has been updated in the database by the plugin during an UPDATE? or simply when the value changes in the browser?
FYI: the form itself has several options for checking change detection i.e. Before DML will mean that you only updated changed values, if you do not use this setting then all fields will be updated for every save.