NURA Sdn Bhd closes its account on 30 March every year. Thus, the basis period for 2018 is 1 April 2018 until 30 March 2019. Prior the start of the basis period NURA Sdn Bhd received a notice to pay the estimated tax for year of assessment 2018 amounting RM360,000. On 20 September, the company revise the tax installment to RM430,000. Later on, 23 December the company revise the tax installment to be RM500,000. At the end of the basis period the actual tax was RM850,000. Required: (a) Calculate the amount tax payable (inclusive of penalty, if any) to IRBM.