Nothing prevents this, but I was hoping to hide all calculations in the class. My present problem is that my app ( FP 2.5 DOS) has been in use for 7 years. Over that time we have developed 6 distinct types of customers. My report files are almost unreadable with conditional if piled upon conditional if. I want to get away from this but insure that the proper code is applied to each customer class, otherwise what is the real advantage of custom classes?