I did check Turbo Tax and it used the mortgage interest deduction in calculating the state taxes in both states. My federal deduction maxed out at $10,000 as it happened to most people. I used standard deduction for my Federal 1040 for a lower total tax amount. Turbo Tax calculated my primary state California taxes based on the full earning and itemized deduction with mortgage interest. After calculating the taxes paid to NY state, Turbo Tax deduct the NY taxes from the CA taxes. I guess the difference is very miner when it is said and done. I only benefited the mortgage interest deduction one time in CA tax calculation because what was lower in NY is now not substrate from CA tax.
