The property taxes and mortgage interest are deducted from your Gross Income. Once these and other applicable deductions are subtracted from your Gross Income, you have an Adjusted Gross Income. When the appropriate amount of tax is assessed, TurboTax evaluates whether you have enough Itemized deductions that amount to more than the $24,000. The Mortgage interest and Property taxes do not fall under Itemized Deductions so they do not factor towards the $24,000 (which is actually in your favor).
