the AI section of form 2210 is difficult to complete because you must compute income, deductions, taxes and credits for each period. Turbotax only does the calculation for the 4th quarter because that's the same as your return. you need to read the instructions for the 2210AI section. here is line 16
Enter all of the other taxes you owed because of events that occurred during the months shown in the column headings. Include the same taxes used to figure Form 2210, Part I, line 2 (except self-employment tax), plus the tax from Form 4972, Tax on Lump-Sum Distributions; Form 8814, Parents' Election To Report Child's Interest and Dividends; and any alternative minimum tax (AMT).
To figure the AMT, Form 1040 or 1040-SR filers use Form 6251; estates and trusts use Schedule I (Form 1041). Figure alternative minimum taxable income based on your income and deductions during the periods shown in the column headings. Multiply this amount by the annualization amounts shown for each column on Schedule AI, line 2, before subtracting the AMT exemption.
