Basis of charging accounting feea

Service costing is best. Use a little bit of abc costing of allocating indirect costs to the product. This is from your end and there is no law that elite clients will pay exuberant prices and poor will pay normal charges. This is you start up company philosophy- whom should you provide services to? And set prices accordingly on a cost plus basis. 

Forgot I made motion, absorption costing is also good and add a margin to your client. Most of the costing  techniques  will give you per unit cost only. What you charge the client is your wish