TurboTax is self-prepared - nobody by you can vouch for the accuracy of your tax return.
It is hard to believe that in this day and age of tax software that there are still lenders that do not understand tax software and self-prepared tax returns. Find someone higher up that has a clue or find a new lender.
And no 3rd party, even it they do your tax, can know if what you tell them is true or not. CPA's that do tax can only say that the tax is correct based on the information that you provided and TurboTax's accuracy guarantee is the same - the calculations are guaranteed based on the information you entered. TurboTax has no way to know if that information is correct or not.
**Disclaimer: This post is for discussion purposes only and is NOT tax advice. The author takes no responsibility for the accuracy of any information in this post.**
