Why same taxable income has two different taxs？

[zhijiexia]

I have encountered an interesting problem with TurboTax.  With foreign income exclusion counted, two returns with the same taxable income (one has foreign income exclusion and one doesn't) have dramatically different tax:
case 1 without foreign income, line 11:128,505,line 15: 103,401, line 16: 12,720

case 2 with 100,000 foreign income and excluded:  line 11:128,505, line 15: 103,401, line 16: 21,334.

Are tax supposed to be determined by the taxable income?  why two such dramatically different results?

[DaveF1006]

if you have a Turbo Tax Software product, compare the capital gains worksheet using both scenarios. Since you have capital gains, your total tax liability is calculated in this worksheet rather than using the tax table.

Compare both and see what the difference is.

[zhijiexia]

I think I found the problem from the capital gain tax worksheet.  

In line 1 b, the sheet asks for the foreign income, which shouldn't be counted if the income meet the exclusion rule and is excluded.  The current TurboTax treat the excluded foreign income the same way as the one which doesn't meet the exclusion rule and is not excluded, which makes the tax much higher.

In my opinion, the foreign income should have been counted in 1040 line 8 (other income) and shouldn't need to be counted again in the capital gain tax worksheet.  

Any way to change or override the values in the worksheet?

I have attached the screen for reference.

[JeffreyR77]

The two examples are not equal. 

Form 1040 Line 11 is adjusted gross income. 

The  examples are not equal if there is adjusted gross income of $128,505 without foreign earned income and another with foreign earned income exclusion of $100,000 as stated and the same adjusted gross income of $128,505. 

The second example has $100,000 more gross income than the first example because it has been subtracted out before adjusted gross income is calculated. 

If you claimed the foreign earned income exclusion, housing exclusion, or housing deduction on Form 2555, you must figure your tax using the Foreign Earned Income Tax Worksheet.

The nonexcluded income in the second example is going to be taxed at the rate it would have been taxed if the excluded income had been included in adjusted gross income. 

The excluded income just isn't subject to tax. Foreign Earned Income Tax Worksheet (see page 33)