Can someone answer me why when I have one of our commercial flights land at OAJ and I have to close the IFR plan out, I used to call D.C. Center directly thinking this would be the best method. Well, one day the center controller got mad at me and said I had to call Flight Data to cancel it. So, then we started calling Flight Data, and the flight data person would say, "ok, I'll call center and close it out." Huh? Isn't calling Center what I had been doing? Why go through a middle-man to do the same thing I could just do myself? I dunno, I found it odd. I still use Flight Data now to cancel it out, but it just seems like it would be faster if I could call center myself.