Mitsu1- The calculator I used is at http://adamone.rchomepage.com/cg_calc.htm.
It says "For an aircraft to be stable in pitch, its CG must be forward of the Neutral Point NP by a safety margin called the Static Margin, which is a percentage of the MAC (Mean Aerodynamic Chord). Static Margin should be between 5% and 15% for good stability. It goes on to say that "Low Static Margin gives less static stability but greater elevator authority..." This is what most 3der's are looking for.
I think what they are saying is the CG should be 5-15% of the MAC ahead of the Neutral Point.