Self-employment income would just increase the AGI and not make a difference. Since the max AGI, for the credit is $19,999.99, and the standard deduction is $26,100, the taxable income will always be $0 and no credit allowed.
It seems that IRS needs to correct the Income Limits for married couples with one spouse less than 65. Without the correction, the "Federal Credit for the Elderly" will be meaningless for those couples.
