Assignment Codes are used to attribute commission items to a rep. Assignment Codes can contain any combination of letters and numbers. They are created when the commission item is created, so basically made when you either import a spreadsheet or transfer them over from another RPM subscriber.
Usage
Assignment codes are mainly used when you have a specific identifier on your spreadsheet or transfer that you would use to assign commissions to your agents. The specific identifier would be something different than the account number since the assigned reps feature is by default using the account number.
So assignment codes has a special unique use case in RPM where for example you may have a sales ID on your commission item imports that you want to use instead of the account number when assigning deals.
Mapping an Assignment Code
When mapping your commission spreadsheets/transfers to your suppliers you can choose a source for the Assignment Code.
Each Assignment Code belongs to a single supplier and Assignment Codes are assigned to a single rep, and if not assigned they are labeled "unassigned".