529 Plan contributions are delt with in Line 29 – Other subtractions of Form IT-203.  The instructions say to include up to $5,000 for an individual, or up to $10,000 for married joint return, in the Federal amount column only.

What are the practical effects of adding 5k or 10k to the Federal column?  Is the taxpayer better off using a 529 plan in their residential state (let say NJ or CT)?