Determination of tax payable by employers and/or enrolled persons:

(1) Where the prescribed authority has, upon information received, reasons to believe that any employer or other enrolled person has paid tax for any year at a rate lower than what is payably by such employer or such person under this Act, it may, after giving such employer or person a reasonable opportunity of being heard, determine in the prescribed manner the amount of tax payable by him. (2) The amount of tax determined under sub-section (1) less the sum, if any, already paid in respect of such year, shall be paid by such persons on demand by the prescribed authority in the prescribed manner.