No, first of all if he can be claimed by you which is evident because you already filed your return, I am making the assumption that he is below the age of 24. Having said that, if I enter fake information (name, ss#, etc.) and enter his $19600 along with Federal Withholding of $1960, with all else being no entries, I am coming up with him getting a refund of $1237 Federal. Please go back and check the entries for your son and make sure that you've entered everything correctly. Something is not adding up based on the information you've provided and the mock return I just ran.
