Generally, the amount which a physician normally or usually cha/-(j(s the majority of his patients. Under Medicare, it is the median charge used by a particular physician for a specified type of service during the calendar year preceding the fiscal year in which a claim is processed. There is therefore, an average delay of a year and a half in recognizing any increase in actual charges. Customary charges in addition to actual and prevailing charges are taken into account in determining reasonable charges under Medicare.