Why would the IRS question Federal withholding from Social Security retirement benefits?
If you have Federal withholding from Social Security retirement benefits, it is reported by SSA to the IRS.
Is there something additional needed when filing with Turbotax that would prevent this extra effort and delay in receiving your over withheld tax? If you need to attach your forms SSA-1099-SM to your original filing, why doesn't Turbotax guide you to do so? How do you do it?
