When you sell your primary house and buy another house, turbotax misclculates the allowable mortgage interest. If the max allowable mortgage for both houses are $750,000, it should caclulate as follows:
Allowable Interest =($750000/Mortgage1) x Interest1+ ($750000/Mortgage2) x Interest2
Instead it treats them as if you have both houses as primary and second home calculating interest as follows:
Allowable Interest = $750000 x (Interest1+Interest2) / (Mortgage1+Mortgage2)
