Why would you want to be certified as a concrete flatwork finisher? What can ACI certification offer you? Do you feel that you know all there is to know about concrete from your own field experience as a contractor, finisher, producer, or project engineer?
Even if you have had years of field experience in concrete placement and training in construction practices, there are many things you may not know about concrete. I recently took the ACI Concrete Finisher class with finishers, superintendents, contractors, and producers, and was surprised at how much I didn't know.