What if you are responsible for working with a supplier whose deliverable to you is TIME. You are purchasing the hours of their employees as they perform tasks for your company. These suppliers charge you an hourly rate. They track their time on your business, and bill you accordingly.
Would you like to have full transparency (budget vs. actual hours ($) incurred/billed by tactic)?
If you answer yes. Then Wanamaker ARMS is the system for you. It will work for any Client/Supplier relationship in which the supplier is billing you hours incurred on your behalf.