When I did percentage my contract was worded in such a way to reflect a % of total PRACTICE REVENUE. Even if the staff is collecting it, it's same amount of work for me. I did not charge lower % either, it's all data entry in posting payments and one is not easier than the other so only stands to reason it's same %. Another reason yet I was glad to get away from the % billing model. Provider's wanted to make their own rules on how this was done.