Since the over withholding is from multiple empyrean I have good news. The easy way is your path. You recover the excess SS withholding straight on the refundable credits portion of your income tax return. This add straight to your bottom line. Any software or tax professional can calculate this for you, although if your first employer had maxed out the $110100 limit for income subject to withholding then its easy, all the SS tax withheld by your second employer is refundable.