Jones Construction (Pty) Ltd, made its second provisional tax payment of R180000 for the 2018 year of assessment on the 31 August 2018 (the last day of its financial year). Its first provisional tax payment for the 2018 year of assessment of R150000 was made on 28 February 2018. Its taxable income for its 2018year of assessment, as finally assessed on 15 August 2019, was R1500000 with a normal tax liability of R420000. Further to the above,

Jones Construction (Pty) Ltd, made an additional provisional tax payment of R135000 on or before 28 February 2019, the last day for making an additional provisional tax payment, it will not be liable for interest on underpayment of provisional tax. If Jones Construction (Pty) ltd, made an additional tax payment of R80000 on or before 28 February 2019, the last day for making an additional provisional tax payment. Calculate any interest that Jones (Pty) Ltd, may be liable for. Disregard any under-payment penalties that may be levied for purpose of this example. 

Assume that the prescribed rate of interest was 10.5% at all relevant time.