I agree with pjvr. What you are describing is a throttle misalignment below crossover, for which there is no limit. If everything else is within limits, there isn't a problem.
If you are still really concerned about this, you could check for air leaks, but you should also have lower torque and slower starts.
You could also adjust the TD Valve and/or Fuel Control, but ONLY if the rich/lean check shows rich AND you have warm start temperatures and well within normal start times.
Otherwise, it sounds like the TD system is doing its job well, and stops controlling when it's supposed to stop controlling.