The problem with line 14 (a)-(c) is related to how TT Form 2210AI scales (QD) and doesn't scale (CG) factors to calculate the impact of CG/QD. This is wrong and not consistent with IRS Pub 505 worksheet 2-8 which would scale both. I ran several tests in TT Form 2210AI where I scaled column (d) inputs down by a factor of 4 and input these into the input locations for Column (a). This results in the same value for total taxable income in line 13 (a) and (d), but different results if the scaled CG/QD income is input as all CG vs all as QD vs split as scaled from column (d). As kevinandlori user noted, TT only scales QD, but not CG. In my tests if all of the scaled CG/QD was input as QD, the results of 14 (a) matched 14 (d), but if it was all input as CG, the calculated tax in 14 (a) was 20% higher than 14 (d). Using IRS Pub 505, worksheet 2-8 gave the same result for both 14 (a) and 14 (d). Bottom line is that if someone has any CG in either of the first three periods, TT will not calculate 14 (a)-(c) correctly, because TT doesn't scale CG per IRS requirements in doing the tax calculation. Fix your program TT.
