How do I get the right amount for sales tax?

I did the IRS Sales Tax Deduction Calculator.  Per IRS:  State=6.2500%.  Local 1.100%.  I entered 7.35%.  Turbo Tax Premeier has my deduction as $797.  IRS has that it is $937.    What income is this based on; Income 1040, Line 7 (taxable), or total income (taxable + nontaxable).   Should I try and override the $797 and change it to $937 or leave it alone?  Thanks