MAT rate for IFSC units reduced where income is solely in convertible foreign exchange to a lower statutory rate. Amendments to MAT under section 115JB treat expenditure and income relating to patent royalty charged under the separate patent royalty provision as items for MAT computation, add a retrospective exclusion of certain foreign companies from MAT where no permanent establishment exists or registration is not required, and provide that units in an International Financial Services Centre deriving income solely in convertible foreign exchange will be subject to MAT calculated at a lower statutory rate, with definitions for IFSC, unit and convertible foreign exchange.