A couple of thoughts spring to mind:
1. It's not just pellet count, but pellet patterning. Is the distribution good, or are there turkey head/spine-sized gaps in the pattern?
2. Pattern so we know the point of impact.
Through my learn-to-hunt work, I see HORRIBLE patterns at 30 yards that are more likely to cause cripples because they're high/low, left/right or just so porous as to be ineffective.
3. Beginners and even experienced turkey hunters misjudge distance; big toms look closer than they are. Having a few extra yards of pattern provides a measure of insurance.
4. I've killed toms at 11 feet. I've also killed 10 toms between 40 and 50 yards (and had zero cripples) because I pattern like crazy.
Try runnings some #7 Federal Heavyweight Mag Shok through your SSX choke. Plenty of energy at 40 yards, and my 20 gauge puts 164 pellets in a 12" circle at 38 yards. See video: http://www.youtube.com/watch?v=R1mSs56HepQ