Hmmm. I'm not sure this is correct. Hopefully Ken or Jared can clarify. I thought what Smart Focus did was monitor the curve and if it is lopsided, restart the routine with new start points in the right direction. I didn't think it forced a weighted average fit. I could be wrong though. I always leave Smart Focus enabled.
I also thought that SGP indicated that it got a good "intersection" fit by coloring the lines green. If one or both lines are red, I thought that meant that it picked a weighted average.
Tim