Payment of interest under payment of gratuity act, 1972.

Hi everybody, I have a confusion regarding the payment of interest under The Payment of Gratuity Act, 1972. As per sec 7, "If the employer fails to pay the gratuity within 30 days of it becoming payable, he shall be liable to pay simple interest....". While sec. 8 states, "The employer shall also be liable to pay compound interest...". What am I missing here? Could somebody please explain what to make of the contradiction? Thanks.