Schedule M is not as complicated as some of us make it out to be.
Get it out of your thinking that a credit was given during 2009. There was no credit given to anyone. The withholding tables were merely adjusted, the theory being that the economy would be stimulated if the taxpayer received a little more money in his/her paycheck.
The 400/800 credit is subject to reduction because of ecoomic recovery payments received (SS,VA and RR) as well as income limits.
Those who are not in the Social Security system and have a government reirement pension (Federal or State) get their $250 on Schedule M. If this is your client be sure to add the Schedule M even though he/she may not have earned income.
taxbilly