Source?
The premise of your question is false.
During the time that illegals are granted their blue cards will they be taxed and the withholding go to the fedgov similar to what the rest of us pay? Is there an option for this money to be held in account for a payout to Mexico or refunded back to the individual?
I'll assume your contention that your figures are true but is it safe to assume that all things will remain equal with the current proposal for a guest worker program? If not then it is an expansion of welfare.
Source?