If you want to offer a multi-level marketing (tier commissions) in your affiliate program, then you can easily manage this scenario in Post Affiliate Pro 4.
Basically, all you need to do is to log into your merchant panel and click on Campaign manager, pick the right Campaign and then click on edit icon:
Then go to Commission settings tab and click on edit button (pick the correct commission type from per Sale / per Click / per Action):
Now all you need to do is to check the option "Support multi tier commissions" and using Add tier button, you can add unlimited number of tiers. (note that 2nd tier is the parent affiliate of the affiliate who actually referred the sale, 3rd tier is the parent of that parent affiliate and so on..)
You can choose also the type of commission: percentage or fixed amount which depends on your main system currency. In our example, there are 5 tiers with percentage commissions:
If you want to remove one of your tiers, you can use "remove last tier" button (the last tier is always removed - in this case the 5th tier).