(b)where as a result of an order of the Settlement Commission under sub-section (4) of section 245D for any assessment year, the amount of total income disclosed in the application under sub-section (1) of section 245C is increased, the assessee shall be liable to pay simple interest at the rate of one per cent. for every month or part of a month comprised in the period commencing on the 1st day of April of such assessment year and ending on the date of such order, on the amount by which the tax on the total income determined on the basis of such order exceeds the tax on the total income disclosed in the application filed under sub-section (1) of section 245C;