As far as info to check, the 1040SR is pretty simple and ditto the SSA1099 sent by social security. I do have an addt'l 1099 that is about the same in simplicity, but I checked for any kind of wrong info and didn't see anything.
The mismatch theory sounds plausible but from what I can check, I do not find any incorrect entries on the 1099s or the 1040SR. Wouldn't t the info I get from SS the same as what IRS gets? Also, since IRS is referring to withholding, is it only then the withholding amount they are questioning? If so, then comparing the w/holding amt submitted against the 1099s is fairly straightforward. The withholding amount is definitely correct.
