You don't have to but to get the most performance out of our solution we generally recommend a custom commission rate or program is defined. We fully support custom affiliate programs via your existing network. Please reach out to your affiliate network to set this up.
Custom programs let you control the terms, but remember that our marketplace environments are competitive: a compelling commission rate helps ensure publishers choose to promote your products. All sites we operate are optimized to generate maximum revenue for all parties involved (you, the marketplace publisher, the affiliate network and us).