www.CompleteTax.com in error?

[Jonathan S.]

Anyone here use CompleteTax.com?
If so, look at your Form 1040 Lines 43 (Taxable Income) and 44 (Tax).
Now look up your figure for Line 43 at:
http://www.irs.gov/pub/irs-prior/i1040tt--2009.pdf
(Just change the year in the url to do this for prior years.)
Do you get the same figure for Tax?

I ask b/c I'm currently completing Form 1040X for years 2007, 2008, and 2009.
(My fault -- not the fault of CompleteTax.com)
The error was in the itemized deductions, so beforehand I multiplied the deduction error by the marginal tax rate to estimate the amount owed.
But when I looked up the corrected taxable income in the IRS tax table (married filing jointly), the amount owed was much higher.
I then realized that part of the amount owed was attributable to a differential between what CompleteTax.com calculated and what is shown in the tax table.
To verify that I was using the correct tax table, etc., I went to a spreadsheet I had previously downloaded from an entirely different source (TaxFoundation.org), and sure enough, when I calculated out the brackets, the tax was within several dollars of the tax table, and once again way many hundreds of dollars higher than what CompleteTax.com calculated at the time.
I keep thinking that I must be doing something wrong, since if CompleteTax.com was submitted incorrectly calculated tax figures, the IRS would catch something like that immediately?!?
(Just out of curiosity, I tried lagging the years -- i.e., using 200X income with 200Y brackets -- and although that reduced the differential, it was still way off.)
I also tried:
http://turbotax.intuit.com/tax-tools...&width=980&s=1
(setting it up so that the taxable income matched my return) and the result matched the official IRS tax table, and was just a few dollars off my own calculations, yet once again inexplicably hundreds of dollars off CompleteTax.com's figure.