clarifying questions
did you mean you took the $17k in deductions and YOU filed 'itemized' and she took standard @ $12k? that creates $29k of deductions where it would only be $24k as joint. (you stated you each took standard) . if you both took standard filing separately , I don't understand the logic in how the taxes would have been so much less.
how did you decide to split the deductions? for example, if she has state withholdings, she has to take those - you can't. Do you own a house TOGETHER? how did you split the mortgage interest and the property taxes? if you took them all, WHY? (and recall by going married-separate, the SALT deduction is maxed at $5,000 for each which motivates splitting and one person not taking it all but it depends who actually made the payments - you or your spouse)
