Why is Q18 box "If you elect to itemize deductions even though they are less than your standard deduction, check here" ticked? Itemized amount is less than standard!

Generally, TurboTax will automatically use the deduction (whether standard or itemized) that is most beneficial in your tax situation. The only time you could be forced to itemized your deductions is if you are filing a married filing separate return and your spouse is itemizing. If you file separately, you must use the same deduction method used as your spouse.

If this not does apply to you, you can force the standard deduction to be used. 

To change your election and force a standard deduction, please follow the steps below: 

1. Open your return.
2. Click on Tax Tools on the left hand side.
3. Click on Tools.
4. Click Topic Search. 
5. Search "itemized deductions, choosing"
6. Click on Change my deduction.
7. Choose Standard Deductions under Which deduction do you want to take this year? 

Yes but this isn’t the case. We are not filing separately. When I force the standard deduction, the amount refund decreases (even though the standard amount is greater than itemized). This is why it makes no sense.  

It could be that you have an alternative tax situation that may limit your standard deduction. If your income is over $113,400, you may be subject for paying Alternative Minimum Tax(AMT) in addition to your regular income taxes. Please read this Turbo Tax link for more details.

Also the standard deduction is not taken into account for AMT purposes thus is added back as AMT income. In addition, certain itemized expenses such as  state and local income tax, real estate taxes and personal property taxes are added back as AMT income. Your mortgage interest and medical expenses are still allowed and may have accounted for the difference between itemized and standard deduction.

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