SCMOde <Sum,Wilson> :

This keyword defines the mode that QS will use for scaling F_c's to F_o's after each Monte Carlo step. The sum option defines a crude but fast scaling based on the quantity $\sum$F_c/$\sum$F_o, whereas wilson defines a Wilson-like scaling mode. Because of the sensitivity of the Monte Carlo algorithm to even small differences between the resulting R factors, I think that you should always use SCMOde Wilson.