Be aware that the withholding is only an estimate. Your actual tax is calculated on your tax return, and you get credit for the withholding. If the withholding was too much, you will get a refund, but if the withholding was not enough, you will owe more taxes.
Yes, you can include your provable gambling losses. However, they will only actually help if you are already planning to itemize your deductions, because you have a mortgage, gifts to charity, and other items. Of course, state income tax is one of the itemized deductions, so just with the Michigan withholding alone ($22K+) you are already very close to the threshold for itemized deductions. If you enter all your tax deductions, Turbotax will determine which method results in the lowest taxes.
No
