I checked Form 5805 after running through the "underpayment penalty" interview section. In Part III (annualized income schedule) Line 6 (annualized itemized deductions) there is an error. Columns (a) through (c) -- for the first three quarters -- all show the correct values. But column (d) is incorrect. This should be the easiest column: since no annualization is needed for Q4, it should exactly match the itemized deductions listed on Form 540. It does not match. I haven't been able to figure out a logical explanation for what it's doing wrong to come up with that particular incorrect value, and there's no worksheet or anything that shows the calculations.
I'll note that my itemized deductions are limited, so the itemized deductions worksheet is used to calculate the deduction amount. This doesn't invalidate anything that I wrote in the previous paragraph: the amount on Line 6(d) of the annualized income schedule should match the final amount of deductions shown on Form 540.
