The error concerns line 26 in column (a) and line 20 in column (c). Any Overpayment in Line 26 should be transfer to Line 20 of column (c), but it does not. Instead, the program enters the Overpayment in Line 20 of column (b). (Column (b) should have no entries since there were only 3, not 4 Estimated Tax payment due dates in 2020. The result of this error is that any overpayment of Estimated Tax for the 7/15/2020 period, the first period, is not considered in the calculations of overpayment or underpayment in column (c), the second period due date. This causes any overpayment for period 1, column (a) to not be considered in calculating the penalty for underpayment.
