<s>[INST] How to calculate interest under Section 234C if the assessee has opted presumptive taxation scheme of Section 44AD or 44ADA? [/INST] ​​​If the assessee has opted presumptive taxation scheme of Sections 44AD or 44ADA and advance tax paid on or before March 15th is less than 100% of the assessed tax, simple interest at the rate of 1% shall be charged for 1 month on the shortfall amount (i.e. 100 % of assessed tax less tax deposited on or before March 15).​​ </s>