As of Feb 21 I suggest you DO NOT USE TURBOTAX for FORM 2210. I have so far found 5 errors in the TurboTax calculation:
1. When using the annualized installment method, line 10 column (a) in part 3 of form 2210 is supposed to be equal to schedule AI line 27 column (a). Instead, it is equal to line 27 column (a) + line 27 column (b).
2. The tax computations on schedule AI, line 14 column (a), (b), and (c) are incorrect.
3. Self-employment tax on line 15 of schedule AI is incorrectly also included in line 16, resulting in a double-counting of self-employment tax and a line 17 column (d) total tax that incorrectly exceeds the total tax shown on form 1040 line 24.
4. 2020 refunds applied to 2021 are supposed to count as a tax payment starting in the first quarter of 2021. Instead, 2020 refunds applied to 2021 are incorrectly ignored on form 2021.
5. Line 7 schedule AI incorrectly excludes amounts on line 12(b) of form 1040.
