As a spin-off from the paperComparison of CPS and Its Assessment Between North America and China”， some academic discussions are held about frequency checking and control performance assessment periods， frequency checking method， methods of improving the CPS1 value， and drawing of conclusions. Meanwhile， it is pointed out that when making an adjustment of the frequency control method， investigations should carefully be made by referring to the actual conditions of Chinas power grids prior to circumspect modification.