1. As far as we can tell, the IRS does keep a separate copy of the SSA database. It seems to be the only explanation since we have seen multiple instances of the IRS and SSA databases being out of step with each other.
2. What does it matter and why do you care? Even if you find proof that the IRS does use a live SSA database and should not reject your return, that won't change the fact that they did reject it and you need to mail it in this year.
