Perhaps you are misreading an indication by TurboTax that your combined state and federal income taxes might be lower if you itemize deductions on your federal tax return to allow itemizing on your state tax return. However, given that the gap between itemized deductions and the federal standard deduction is rather large, it's doubtful that doing so would be beneficial.
Confirm the amount of the deduction actually being used by looking at line 9 of your Form 1040.
