Help! Are there multiple definitions for MAGI? If you work through the worksheets in 590, it appears as though MAGI for the purpose of making a deductible IRA contribution is different from MAGI for making a Roth IRA contribution.

This also has me wondering which definition of MAGI will apply for the application of the 3.8% Medicare surtax beginning in 2013. Am I missing something with the definition and calculation?