...

Affiliate Commissions

This section is used to apply a commission for the item to each of the configured Commission Groups in the affiliate management Affiliate Management program:

Merchants that have configured many affiliate groups in their affiliate management program may benefit from configuring new items into their affiliate commission groups directly from the item editor.
The primary benefit to using the configuration section in the item editor its that it allows you to quickly assign the proper group level commissions without needing to edit each commission group directly.

...

The second way of calculating the arbitrary unit cost for an item is with velocity code. We have a tutorial on using arbitrary cost calculation for a pro-rated cable subscription /wiki/spaces/AR/pages/1376664.

Channel Partner Item Mapping

...