Our Recurly billing integration provides the following functionality:
Fixed monthly fees (e.g. $50 per month)
Fixed perorder fees (e.g. $0.50 per order)
Percentage perorder fees (e.g. 5% per order)
Fixed fax fees (e.g. $0.10 per fax sent)
Any other billing would have to be done manually. If you have a complex billing scenario, please let us know we may not be able to support it, but we can potentially help.